Husqvarna Chainsaw 340 345 346XP350 351 353 User Manual
Workshop manual  
340 345 346XP  
350 351 353  
English  
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Introduction  
Arrangement of the manual  
Troubleshooting  
This workshop manual can be used in two different  
ways.  
These pages describe the most common faults that  
affect a chainsaw. They are divided into four  
different groups with the most likely faults de-  
scribed first.  
• To repair a specific sub-assembly on a chainsaw.  
• To dismantle and reassemble a complete  
chainsaw.  
Repair instructions  
The section that describes how to repair the  
chainsaw consists of detailed, step-by-step instruc-  
tions. It explains in detail the special tools, lubri-  
cants and bolt torques that are needed when  
working on each component.  
Repairing a specific sub-assembly  
If a specific sub-assembly on the chainsaw needs  
to be repaired:  
1. Look up the page referring to the relevant sub-  
assembly.  
2. Follow the instructions under the headings:  
Removal/Dismantling  
Cleaning and inspection  
Refitting/Reassembly  
This workshop manual covers the following  
chainsaw models:  
Dismantling and reassembling the entire  
chainsaw  
340  
345  
346XP  
350  
351  
If the entire chainsaw is to be dismantled, follow  
the instructions under the heading “Removal/  
Dismantling”.  
353  
Work through the manual and follow the instruc-  
tions given in each section under the heading  
“Removal/Dismantling”.  
Then follow all the “Cleaning and inspection”  
instructions in each section.  
Working from the back of the manual, follow all the  
instructions under the headings “Refitting/  
Reassembly” in reverse order.  
Each of the sections covering removal/dismantling  
and refitting/reassembly include the relevant  
lubrication instructions and bolt torques for each  
stage of repair.  
Construction and function  
This chapter gives a simple description of the  
chainsaw carburettor and its various parts.  
2 – English  
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Safety regulations  
General instructions  
Special instructions  
This workshop manual gives detailed instructions  
on how to troubleshoot, repair and test a chainsaw.  
This section also describes the various safety  
The fuel that is used in a chainsaw poses the  
following hazards:  
precautions that should be taken when carrying out • The fuel and its fumes are toxic.  
repairs.  
• May cause irritation to skin or eyes.  
• May cause breathing difficulties.  
• Highly flammable.  
The workshop manual has been written for person-  
nel who are assumed to have general experience  
of repairing and servicing chainsaws.  
When using compressed air the air jet should  
never be pointed at the body. Air can be forced into  
the bloodstream and cause fatal injury.  
Workshops where chainsaws are repaired must be  
equipped with safety equipment that meets local  
regulations.  
Wear ear protection when testing saws.  
No-one should carry out repairs on a chainsaw  
until they have read and understood the contents  
of this workshop manual.  
After testing a saw do not touch the silencer until it  
has cooled down. The silencer gets very hot and  
you may burn yourself. Wear protective gloves  
when working on the silencer.  
Chainsaws are type-approved to meet the relevant  
safety legislation, but this only applies when the  
saw is fitted with the cutting equipment specified in  
the user’s manual. The fitting of any other equip-  
ment, or of accessories or parts that are not  
approved by Jonsered, could mean that the saw no  
longer meets these safety requirements and the  
person who carried out the work may be held  
responsible for its non-conformance.  
The guide bar, chain and clutch cover (chain brake)  
must be fitted before the saw is started. If not, the  
clutch may come loose and cause injury.  
Poor chain lubrication can result in failure of the  
chain, which could cause serious or fatal injury.  
Take care to ensure that the spring inside the  
starter assembly does not fly out and cause injury.  
Wear eye protection. If the spring is under com-  
pression when the pulley is removed it could fly out  
and cause injury.  
In this workshop manual the following boxes  
indicate where caution should be taken.  
WARNING!  
The warning text warns of the risk  
of personal injury if the instruc-  
tions are not followed.  
Before removing the tensioning spring from the  
chain brake, ensure that the brake is in the on  
position, otherwise the spring may fly out and  
cause injury.  
After completing the repair the chain brake must be  
tested, see “Chain brake – reassembly \ Operating  
test”.  
NOTE!  
The warning text warns of the risk of  
material damage if the instructions are  
not followed.  
Always consider the fire risk. A chainsaw can  
produce sparks that could start a fire.  
Inspect the chain catcher and replace it if it is  
damaged.  
English – 3  
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Special tools  
1
2
3
4
5
6
8
7
9
10  
11  
12  
13  
14  
4 – English  
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Special tools  
15  
16  
17  
18  
19  
20 b  
20 c  
Item Description  
Used for  
Order no.  
1
2
3
4
5
6
7
8
9
Clutch tool  
Piston stop  
Stop plate  
Fuel filter hook  
Allen key  
Centrifugal clutch  
Locking crankshaft  
Locating intake gaiter  
Withdrawing the fuel filter  
For M5 bolts  
502 54 16-01  
502 54 15-01  
502 54 17-01  
502 50 83-01  
502 50 18-01  
504 90 90-02  
20 a  
Puller  
Frame bearing  
21  
Removal tool  
Remove seal from clutch side 502 50 55-01  
502 54 21-01  
Sealing during pressure testing 502 54 11-02  
Mandrel, sealing ring Removing crankshaft  
Cover plate  
10 Pressure tester  
11 Feeler gauge  
12 Clamp stand  
13 Pressure gauge  
14 Piston fitting kit  
15 Test plug  
Connection to cylinder  
Adjusting ignition module  
Clamping the saw  
Pressurisation during testing  
Fitting piston  
503 84 40-02  
502 51 34-02  
502 51 02-01  
502 50 38-01  
502 50 70-01  
502 71 13-01  
502 71 14-01  
502 51 61-01  
502 50 37-01  
502 50 06-01  
502 50 30-18  
502 50 30-18  
502 50 30-18  
502 54 18-01  
Checking ignition module  
Adjusting carburettor  
Removing crankshaft  
Vacuum test  
16 Rev counter  
17 Removal tool  
18 Vacuum gauge  
19 Assembly pliers  
20a Sleeve  
23  
Fitting spark plug guard  
Fitting crankshaft  
20b Shaft extension  
20c Shaft extension  
21 Stop plate  
Flywheel side  
Clutch side  
Removing crankshaft  
22 Assembly tool  
23 Crankshaft tool  
Assembling spring, chain brake 502 50 67-01  
Fitting crankshaft seal 502 50 30-16  
English – 5  
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Technical data  
Displacement  
Cylinder bore  
Ø mm/Ø inches  
Stroke  
mm/inches  
Max power/speed  
kW/hp/rpm  
cm3/cubic inches  
340:  
345:  
40,8 / 2,44  
45,0 / 2,75  
45,0 / 2,75  
49,4 / 3,01  
51,7 / 3,15  
49,4 / 3,01  
51,7 / 3,15  
40 / 1,57"  
42 / 1,65"  
42 / 1,65"  
44 / 1,73"  
45 / 1,77"  
44 / 1,73"  
45 / 1,77"  
32 / 1,28"  
32 / 1,28"  
32 / 1,28"  
32 / 1,28"  
32 / 1,28"  
32 / 1,28"  
32 / 1,28"  
2,0 / 2,7 / 9 000  
2,2 / 3,0 / 9 000  
2,5 / 3,4 / 9 600  
2,3 / 3,1 / 9 000  
2,3 / 3,1 / 9 000  
2,3 / 3,1 / 9 000  
2,4 / 3,3 / 9 000  
346XP/G:  
350:  
350 EPA:  
351/G:  
353/G:  
Spark plug gap  
mm/inches  
Ignition system  
Air gap  
mm/inches  
Carburettor type  
340:  
345:  
0,5 / 0,02"  
0,5 / 0,02"  
0,5 / 0,02"  
0,5 / 0,02"  
0,5 / 0,02"  
0,5 / 0,02"  
0,5 / 0,02"  
SEM CD  
SEM CD  
SEM CD  
SEM CD  
SEM CD  
SEM CD  
SEM CD  
0,3 / 0,012"  
0,3 / 0,012"  
0,3 / 0,012"  
0,3 / 0,012"  
0,3 / 0,012"  
0,3 / 0,012"  
0,3 / 0,012"  
Walbro HDA 195  
Walbro HDA 195  
Zama C3-EL17  
Walbro HDA 195  
Zama C3-EL18  
Zama C3-EL17  
Zama C3-EL17  
346XP/G:  
350:  
350 EPA:  
351/G:  
353/G:  
Effective cutting length  
cm/inches  
Chain speed at  
max power – revs  
m/s – rpm  
Chain pitch  
mm/inches  
Drive link  
mm/inches  
340:  
345:  
30-48 / 12"-19"  
30-48 / 12"-19"  
30-48 / 12"-19"  
30-48 / 12"-19"  
30-48 / 12"-19"  
30-48 / 12"-19"  
30-48 / 12"-19"  
17,3 / 9 000  
17,3 / 9 000  
18,5 / 9 600  
17,3 / 9 000  
17,3 / 9 000  
17,3 / 9 000  
17,3 / 9 000  
8,25 / 0,325"  
8,25 / 0,325"  
8,25 / 0,325"  
8,25 / 0,325"  
8,25 / 0,325"  
8,25 / 0,325"  
8,25 / 0,325"  
1,3 / 0,050" - 1,5 / 0,058"  
1,3 / 0,050" - 1,5 / 0,058"  
1,3 / 0,050" - 1,5 / 0,058"  
1,3 / 0,050" - 1,5 / 0,058"  
1,3 / 0,050" - 1,5 / 0,058"  
1,3 / 0,050" - 1,5 / 0,058"  
1,3 / 0,050" - 1,5 / 0,058"  
346XP/G:  
350:  
350 EPA:  
351/G:  
353/G:  
6 – English  
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Technical data  
rpm  
Idling speed Engagement speed  
Max. speed  
rpm  
Spark plug  
rpm  
rpm  
340:  
345:  
2 700  
2 700  
2 700  
2 700  
2 700  
2 700  
2 700  
3 800  
3 800  
3 800  
3 800  
3 800  
3 800  
3 800  
12 500  
12 500  
14 200  
13 000  
13 000  
13 000  
13 000  
NGK BPMR 7A, Champion RCJ 7Y  
NGK BPMR 7A, Champion RCJ 7Y  
NGK BPMR 7A, Champion RCJ 7Y  
NGK BPMR 7A, Champion RCJ 7Y  
NGK BPMR 7A, Champion RCJ 7Y  
NGK BPMR 7A, Champion RCJ 7Y  
NGK BPMR 7A, Champion RCJ 7Y  
346XP/G:  
350:  
350 EPA:  
351/G:  
353/G:  
GAS  
OIL  
Fuel tank capacity  
Litres/US pints  
Oil pump capacity at  
8,500 rpm,  
Oil tank capacity  
Litres/US pints  
Automatic oil pump  
ml/min  
340:  
345:  
0,5 / 1,05  
0,5 / 1,05  
0,5 / 1,05  
0,5 / 1,05  
0,5 / 1,05  
0,5 / 1,05  
0,5 / 1,06  
9
9
0,25 / 0,53  
0,25 / 0,53  
0,28 / 0,59  
0,26 / 0,55  
0,26 / 0,55  
0,28 / 0,59  
0,28 / 0,59  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
346XP/G:  
350:  
350 EPA:  
351/G:  
353/G:  
5 - 12  
5 - 12  
5 - 12  
5 - 12  
5 - 12  
Weight without bar and chain  
kg / lbs  
Weight with bar and chain  
Heated hand grips  
kg / lbs  
340:  
345:  
4,7 / 10,3  
4,7 / 10,3  
4,8 / 10,6  
4,9 / 10,8  
4,8 / 10,6  
4,8 / 10,6  
4,8 / 10,6  
4,9 / 10,8  
5,0 / 11,0  
5,1 / 11,2  
5,5 / 12,1  
5,5 / 12,1  
5,6 / 12,2  
5,7 / 12,4  
5,6 / 12,2  
5,6 / 12,2  
5,6 / 12,2  
5,7 / 12,4  
5,8 / 12,6  
5,9 / 13,0  
-
-
-
346XP:  
346XPG:  
350:  
350 EPA:  
351:  
351G:  
353:  
353G:  
Yes  
-
-
-
Yes  
-
Yes  
English – 7  
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Construction and function  
The carburettor works in different ways depending  
on the setting:  
Carburettor  
The carburettor consists of three sub-systems:  
• Cold start mode  
• Idling mode  
• Part throttle mode  
• Full throttle mode  
• The metering unit (A) which contains the jets  
and the fuel control mechanism. This measures  
out the right amount of fuel to suit the speed of  
the saw and the power demand.  
In the cold start mode the choke valve (D) is  
completely closed. This increases the vacuum in  
the carburettor so that fuel is sucked through the  
diffuser jets faster (E).  
• The mixing unit (B) consists of the choke,  
diffuser jets and throttle valve. This is where the  
air and fuel are mixed to create a flammable  
mixture.  
• The pump unit (C) pumps fuel from the tank to  
the metering system inside the carburettor. One  
side of the pump diaphragm is connected to the  
crankcase and pulses as a result of pressure  
changes in the crankcase. The other side of the  
diaphragm sucks in the fuel.  
In idling mode the throttle valve (F) is closed. Air is  
sucked through an aperture in the throttle valve  
and a small amount of fuel is supplied through the  
diffuser jet (E).  
8 – English  
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Construction and function  
In part throttle mode the throttle valve (F) is par-  
tially open. Fuel is supplied through the diffuser jets  
(E).  
In full throttle mode both valves are open and fuel  
is supplied through all the diffuser jets (E).  
English – 9  
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Troubleshooting  
The various faults that can affect a chainsaw are divided into four groups. In each group the likely symp-  
toms are given on the left and possible causes are listed on the right. The most likely faults are given first,  
and so on.  
Starting  
Idling (low rpm) (cont.)  
Difficulty starting Adjust L screw  
Air filter blocked  
Idles when L  
screw closed  
Worn needle valve  
Leaking control diaphragm/  
cover plate  
Needle valve assembly sticking  
Worn needle valve lever  
Faulty diffuser jet  
Choke not working  
Worn choke pivot  
Worn choke valve  
Fuel filter blocked  
Fuel line blocked  
Piston ring seized  
Blocked impulse channel  
Idling uneven  
Fuel filter blocked  
Fuel line blocked  
Leaking air intake hose (rubber)  
Loose carburettor mounting  
bolts  
Carburettor  
leaking fuel  
Loose or faulty fuel pipe  
Hole in diaphragm  
Worn needle valve  
Worn throttle valve pivot  
Loose throttle valve screw  
Worn throttle valve  
Needle valve assembly  
sticking  
Needle valve assembly sticking  
Needle valve set too high  
Leak in metering system (air  
or fuel)  
Loose cover on carburettor  
pump side  
Leak in metering system (air  
or fuel)  
Metering system centre knob  
is worn  
Hole in diaphragm  
Leaking control diaphragm/  
cover plate  
Flooding when  
engine not  
running  
Worn needle valve  
Needle valve set too high  
Needle valve assembly sticking  
Crankcase leaking  
Idling (low rpm)  
L screw requires Fuel line blocked  
Will not idle  
Adjust L screw  
constant  
Needle valve set too high  
Leaking air intake hose  
(rubber)  
Loose carburettor mounting  
bolts  
Loose or faulty fuel hose  
Fuel filter blocked  
Fuel line blocked  
adjustment  
Needle valve assembly sticking  
Leak in metering system (air  
or fuel)  
Leaking control diaphragm/  
cover plate  
Faulty diffuser jets  
Crankcase leaking  
Fuel tank vent blocked  
Throttle valve pivot stiff  
Throttle pushrod sticking  
Defective throttle return spring  
Bent throttle stop  
Too much fuel at Needle valve set too high  
idling  
Needle valve assembly sticking  
Metering system damaged  
Worn needle valve  
Faulty diffuser jet  
Leaking control diaphragm/  
cover plate  
Idling too rich  
Adjust L screw  
Metering system incorrectly  
assembled  
Worn needle valve  
Needle valve set too high  
Worn needle valve lever  
Leaking control diaphragm/  
cover plate  
Needle valve assembly  
sticking  
10 – English  
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Troubleshooting  
High rpm  
Acceleration and retardation  
Will not run at Adjust H screw  
Does not  
accelerate  
Adjust L screw  
Adjust H screw  
Blocked air filter  
Blocked fuel tank vent  
Blocked fuel filter  
full throttle  
Blocked air filter  
Blocked fuel tank vent  
Blocked fuel filter  
Fuel line blocked  
Loose or damaged fuel hose  
Impulse channel leaking  
Impulse channel blocked  
Loose cover on carburettor pump  
side  
Fuel line blocked  
Loose or damaged fuel hose  
Impulse channel blocked  
Loose cover on carburettor pump  
side  
Faulty pump diaphragm  
Leaking air intake hose (rubber)  
Loose carburettor mounting bolts  
Needle valve set too low  
Metering system damaged  
Metering system incorrectly  
assembled  
Faulty pump diaphragm  
Leaking air intake hose (rubber)  
Loose carburettor mounting bolts  
Needle valve set too low  
Metering system incorrectly  
assembled  
Needle valve assembly sticking  
Faulty diffuser jets  
Blocked silencer  
Leaking control diaphragm/cover  
plate  
Needle valve assembly sticking  
Blocked silencer  
Adjust L screw  
Adjust H screw  
Faulty pump diaphragm  
Needle valve set too high  
Needle valve assembly sticking  
Faulty diffuser jets  
Engine stalls  
when throttle  
released  
Low power  
Adjust H screw  
Blocked fuel tank vent  
Blocked fuel filter  
Impulse channel leaking  
Impulse channel blocked  
Loose cover on carburettor pump  
side  
Faulty pump diaphragm  
Blocked air filter  
Needle valve assembly sticking  
Leak in metering system (air or fuel)  
Metering system incorrectly  
assembled  
Adjust L screw  
Adjust H screw  
Blocked air filter  
Faulty pump diaphragm  
Faulty diffuser jets  
Over rich  
acceleration  
Loose diaphragm rivet  
Hole in diaphragm  
Troubleshooting methods  
Leaking control diaphragm/cover  
plate  
In addition to the faults described in the above  
table, trouble shooting can be carried out on  
specific components or sub-systems of the  
chainsaw. The various procedures are described in  
the relevant chapters, see the contents page, as  
follows:  
Will not “four- Blocked fuel tank vent  
stroke”  
Blocked fuel filter  
Fuel line blocked  
Loose or damaged fuel hose  
Impulse channel leaking  
Impulse channel blocked  
Loose cover on carburettor pump  
side  
Faulty pump diaphragm  
Leaking air intake hose (rubber)  
Loose carburettor mounting bolts  
Needle valve set too low  
Leak in metering system (air or fuel)  
Metering unit incorrectly assembled  
Loose diaphragm rivet  
Hole in diaphragm  
•
•
•
•
•
Checking the operation of the chain brake  
Measuring the resistance of the stop plate  
Pressure testing the carburettor  
Pressure testing the decompression valve  
Pressure testing the cylinder  
Leaking control diaphragm/cover  
plate  
English – 11  
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Repair instructions  
3
Chain brake – dismantling  
1
WARNING!  
Make sure the spring does not fly  
out and cause injury. Wear eye  
protection.  
Disengage the brake by pushing the kickback  
guard backwards. Unscrew the guide bar bolts and  
remove the clutch cover, chain and guide bar.  
Remove the screws and carefully remove the cover  
from the chain brake spring.  
4
2
Place one hand over the spring and insert a small  
screwdriver between the bottom end of the spring  
and the clutch cover. Carefully prise the spring  
upwards so that it slides onto the screwdriver shaft.  
Grip the clutch cover carefully in a vice. Release  
the brake spring by using the kickback guard from  
the saw as a tool. Engage it with the brake mecha-  
nism and turn anticlockwise to activate the brake.  
Cleaning and inspection  
• Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the damaged  
parts with new ones. Always use original parts.  
• Measure the thickness of the chain brake band.  
It must be no less than 0.6 mm at any point.  
• Lubricate the elbow joint with grease.  
min 0,6 mm  
12 – English  
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Repair instructions  
4
Chain brake – reassembly  
1
Bolt the elbow joint to the brake band and tighten  
to a torque of 1–1.5 Nm.  
Locate the elbow joint and connected brake band  
in their recesses in the clutch cover. Lubricate the  
recess for the spring with grease.  
Tension the brake spring by using the kickback  
guard from the saw as a tool. Engage it with the  
brake mechanism and turn clockwise to release  
the brake.  
2
5
Turn the chain tensioner anticlockwise as far as it  
will go.  
WARNING!  
Make sure the spring does not fly  
out and cause injury. Wear eye  
protection.  
Refit:  
• guide bar  
• chain  
• clutch cover  
NOTE!  
After completing the repair the chain  
brake must be tested as described below.  
Operating test:  
The engine must not be running during the test.  
Guide bar length  
38cm/15"  
Height  
Grip the clutch cover in a vice. Compress the  
spring with special tool 502 50 67-01 and push it  
down with your thumb.  
50 cm/20"  
• Hold the chainsaw over a firm surface. The  
height of the guide bar above the surface is  
given in the table above.  
3
• Let go of the front handle and let the chainsaw  
fall towards the surface.  
• When the guide bar hits the surface the chain  
brake must engage.  
Fit the cover over the chain brake spring, tightening  
the screws to a torque of 1–1.5 Nm.  
English – 13  
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Repair instructions  
Silencer – removal  
Silencer – refitting  
1
WARNING!  
If the saw is equipped with a spark arrestor mesh  
this should be fitted first.  
Do not touch the silencer until it  
has cooled down, otherwise you  
may burn yourself.  
2
Refit  
1
• cooling plate  
• gasket  
• silencer, tighten bolts to a torque of 8–10 Nm.  
• silencer support  
• cylinder cover  
3
Run the saw for at least 1 minute, then retighten  
the silencer bolts to 8–10 Nm.  
Chain catcher – replacement  
If the chain catcher is worn it must be replaced with  
a new one.  
Remove the cylinder cover, silencer support,  
silencer, gasket and cooling plate.  
1
Release the brake by pushing the kickback guard  
backwards. Undo the guide bar bolts and remove  
the clutch cover, chain and guide bar.  
2
If the saw is fitted with a spark arrestor mesh this  
must also be removed.  
2
Cleaning and inspection  
Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the damaged  
parts with new ones.  
The spark arrestor mesh is best cleaned with a  
wire brush. If the mesh is damaged it must be  
replaced.  
If the mesh is blocked the saw will overheat and  
this will cause damage to cylinder and piston.  
Never use the saw with a silencer that is in poor  
condition. Always use original parts.  
Remove the chain catcher and replace it with a  
new one. Check that the vibration damping spring  
locates correctly against the crankcase when you  
bolt the new chain catcher in position.  
A worn (damaged) chain catcher on 340, 345 or  
350 can be replaced with the same chain catcher  
as 346XP, 351 and 353 (see figure above).  
3
Turn the chain tensioner anticlockwise as far as it  
will go.  
Refit:  
• guide bar  
• chain  
• clutch cover  
14 – English  
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Repair instructions  
Stop switch – removal  
Cleaning and inspection  
1
Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the damaged  
parts with new ones. Always use original parts.  
Remove the cylinder cover and air filter.  
2
Stop switch – resistance measurement  
Clean the mating surfaces and check the resist-  
ance as follows:  
Disconnect both leads from the stop plate and stop  
switch. Remove the stop plate by carefully sliding it  
over the lug on the front mounting.  
3
Measure the resistance by connecting a multimeter  
to the ignition coil. NOTE! The switch must be in  
the “on” position to give the correct reading.  
The resistance must not be higher than 0.2 ohm  
when the switch is in the on position.  
Carefully prise the carburettor assembly off the left-  
hand rubber mounting using a small screwdriver.  
4
Carefully prise the stop switch’s upper mounting off  
the air filter holder while lifting the switch to release  
it from the lower mounting.  
English – 15  
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Repair instructions  
Stop switch – refitting  
Choke control – removal  
1
1
Remove the cylinder cover, air filter and stop  
switch. Disconnect the fuel hose from the carburet-  
tor.  
NOTE!  
Do not use knurled pliers to disconnect or  
reconnect the fuel hose. This could  
damage the hose and lead to leakage or  
fracture.  
A
2
C
Carefully press the new stop switch into place.  
Check that the switch’s upper mounting clips over  
the air filter holder.  
B
2
Disconnect the pushrod from the carburettor by first  
carefully prising up the spring over the end of the  
rod, where it connects to the throttle lever (A). Then  
press the throttle lever forwards (B) while pressing  
the throttle pushrod backwards (C) and lifting it off  
the lever. Withdraw the throttle pushrod from the  
tank and lift it upwards without pulling it through the  
rubber inlet manifold. Carefully release the carbu-  
rettor assembly from the right-hand rubber mount-  
ing and lift it upwards.  
Refit the stop plate. Engage the stop plate in the  
front slot first then lift the rear edge onto the stop  
switch. Slide the stop plate in as far as it will go.  
3
3
Refit:  
• the leads to the stop plate and stop switch  
• air filter  
• cylinder  
Compress the clip that holds the choke control to  
the carburettor while pulling it out at the same time.  
Disconnect the choke control from the air filter  
holder.  
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Repair instructions  
Choke control – refitting  
Cleaning and inspection  
First reattach the choke control to the air filter, then  
press it onto the carburettor so that the clips engage.  
• Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the damaged  
parts with new ones. Always use original parts.  
Then refit:  
• Lubricate the throttle lock with oil.  
• stop switch  
• Check that the spring is not broken and has not  
• carburettor into its rubber mountings  
lost its tension.  
• throttle pushrod into the fuel tank and connect to  
throttle lever.  
Throttle lock, throttle trigger and return  
spring – refitting  
• lift the spring arm over the throttle pushrod  
• fuel hose to the carburettor  
1
• air filter and cylinder cover  
Throttle lock, throttle trigger and return  
spring – removal  
A
1
B
A
Refit the return spring to the throttle trigger as  
shown. Make sure the spring is correctly positioned  
by engaging one end in the slot in the throttle  
trigger (A).  
C
2
First insert the rear edge of the throttle trigger into  
the tank. Then push/clip the front edge into the two  
clips on the tank with the aid of a combination tool,  
for example. Drive in the steel pin from the clutch  
side. Use a 2.5 mm/0.1" diameter drift.  
Remove the throttle lock by pressing it to the left  
(A) and carefully levering it up with a screwdriver  
on the clutch side (B) of the saw to disengage the  
lugs on either side of the throttle lock from the fuel  
tank. When both lugs are clear of the tank, pull the  
lock backwards (C).  
2
3
A
Then press down the return spring while pressing  
the throttle lock forwards/upwards into the retaining  
clip in the fuel tank until you hear a click. Release  
the return spring in the throttle lock, then press the  
lock down onto the tank.  
C
Drive out the steel pin using a 2.5 mm/0.1" diam-  
eter drift (A). Push it out from the flywheel side of  
the saw. Remove the throttle trigger by first press-  
ing it towards the clutch side of the saw (B) until it  
clicks, then towards the flywheel side until it clicks  
again. Remove it from the tank and lift out the  
return spring.  
4
Check the operation of the throttle lock by trying to  
press the throttle trigger without pressing down the  
throttle lock. Also check that the throttle lock and  
throttle trigger return freely to their original posi-  
tions when released.  
English – 17  
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Repair instructions  
2
Hand grip heater on model 346XPG,  
351G, 353G – removal  
Reconnect the lead and refit the hand grip cover  
and cylinder cover.  
No heating or heating only in front hand grip  
• Switch – troubleshooting  
• Front hand grip – troubleshooting  
1
1
Carefully free the switch and frame from the front  
hand grip using a screwdriver.  
2
Disconnect the leads from the switch and connect  
a multimeter to it. The meter should read over  
1000 ohm when the switch is in the “0” position.  
The meter should read no higher than 0.1 ohm with  
the switch in the “1” position. Replace the meter if  
the readings are outside these limits.  
Rear hand grip heater not working  
• Rear hand grip heater – troubleshooting  
1
Remove the cylinder cover, air filter and cover from  
the rear hand grip.  
Remove the three bolts that secure the cover over  
the front hand grip. Disconnect the leads from the  
switch and generator and measure the resistance of  
the hand grip heater, which should be 3–4 ohm.  
Replace the front hand grip if the resistance is higher.  
2
Disconnect the red lead from the heater and  
connect a multimeter between it and the black  
earth lead that is bolted to the bottom of the  
carburettor on the clutch side of the saw. The  
meter should read 0.7–1.2 ohm. If the reading is  
higher replace the heater element.  
2
3
Remove the air filter, throttle pushrod, rubber  
diaphragm and carburettor, see “Carburettor –  
removal”.  
4
Remove the bolt from the plate at the base of the  
carburettor to release the lead for the heater  
element.  
5
Reconnect the leads and refit the cover.  
3
Push the switch back into place and reconnect the  
leads.  
4
Bolt the cover back onto the hand grip.  
• Generator – troubleshooting  
1
Remove the cylinder cover and cover from the  
front hand grip. Disconnect the black lead from the  
generator and connect a multimeter between it and  
a clean area on the cylinder. The multimeter should  
show a resistance of 0.9–1.3 ohm. If the reading is  
higher or lower, replace the generator, see “Re-  
placing the generator”.  
Unscrew the three bolts from the front hand grip  
and remove the cover to reveal the leads. Discon-  
nect the red lead.  
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Repair instructions  
Rear handle heater  
6
Measure the resistance between F and Z. It should  
be 1 0.5 ohm.  
If not, replace the rear handle heater.  
Generator  
Measure the resistance between G and H. It  
should be between 0.3–1.3 ohm.  
If not, replace the generator.  
Carburettor heater  
Disconnect the lead at X and clean the connectors.  
Measure the resistance between X and G.  
The reading should be between 3–10 ohms. If not,  
disconnect the lead at Y and clean the connectors.  
Measure the resistance between X and Y, if the  
reading is not between 3–7 ohms – replace the  
carburettor heater.  
O
O
Unscrew the two bolts from the right side of the  
rear hand grip. Remove the throttle lock and  
throttle handle, see “Throttle trigger”. Pull out the  
heater element with the leads still connected.  
Z
Z
5
5
N
N
F
F
G
G
3
Troubleshooting carburettor heater  
(346XPG, 351G, 353G)  
3
K
KV  
V
X
X
Operation  
The carburettor temperature is controlled by an  
electronic thermostat to eliminate the risk of ice  
formation in the carburettor. The thermostat  
switches on/off at 12°C/54F. This means that the  
saw operator does not need to remember to switch  
the carburettor heater on or off.  
4
4
• Troubleshooting  
Front handle heater  
1
1
Remove the side cover from the handle. Discon-  
nect the leads at F and G (see diagram).  
Clean the connectors. Turn the switch ”on”.  
Measure the resistance between F and G.  
The reading should be 4 1 ohms. If not, discon-  
nect the lead at O and remove the switch.  
Measure the resistance between O and F. The  
reading should be 4 1 ohms. If the resistance is  
incorrect, replace the front handle.  
Y
Y
H
H
Disconnect the lead at N and G and measure the  
resistance between these points. The reading  
should be no higher than 0.1 ohm. If it is too high,  
replace the lead.  
Switch  
Measure the resistance between N and O with the  
switch turned off. The reading should be 1 000  
ohms or higher.  
Repeat the measurement with the switch turned  
on. The reading should be no higher than 0.1 ohm.  
If it is too high, replace the switch.  
English – 19  
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Repair instructions  
Heater element and rear hand grip –  
removal  
Hand grip heater on model 346XPG,  
351G, 353G – refitting  
1
1
Remove the cylinder cover, hand grip cover, hand  
grip and right-hand stop.  
Feed the leads into the rear hand grip and insert  
the heater element in the hand grip. Screw in the  
two bolts through the right side of the hand grip to  
secure the heater.  
Then remove:  
• throttle lock, throttle trigger and recoil spring,  
see “Throttle trigger”.  
2
• fuel hose and throttle pushrod from the carburettor  
Unbolt the rear tank mounting from the crankcase,  
i.e. the rear vibration damping spring, and both  
stops. Lower the tank as far as it will go to allow  
access to the heater lead where it is connected to  
the tank.  
Refit:  
Press the black lead into the base of the carburet-  
tor and connect it with the bolt.  
Tighten to a torque of 3–4 Nm.  
• fuel tank with both stops and the rear vibration  
damping spring  
• throttle lock, throttle trigger and recoil spring,  
see “Throttle trigger”.  
3
Run the red lead to the front hand grip and connect  
it.  
• fuel hose and throttle pushrod to the carburettor  
(check that the hose is not trapped between the  
tank and crankcase, measurement 43 mm/1.69  
inches)  
4
Press the throttle trigger and throttle lock into  
position and check that they work correctly, see  
“Throttle trigger”.  
• hand grip cover, air filter and cylinder cover  
5
Heater element and rear hand grip –  
removal  
1
Screw the heater element into place using the two  
screws and feed the leads through the rear hand  
grip. Secure the red lead in the clip on the tank and  
connect it. Feed the black lead through crankcase  
and secure/earth it to the base of the carburettor  
using the bolt at the front on the clutch side of the  
saw. Tighten to a torque of 3–4 Nm.  
2
Refit:  
• fuel tank with both stops and the rear vibration  
damping spring  
Bolt the vibration damping springs that hold the  
tank unit back in place and refit the cover over the  
front hand grip.  
• throttle lock, throttle trigger and recoil spring,  
see “Throttle trigger”.  
• fuel hose and throttle pushrod to the carburettor  
(check that the hose is not trapped between the  
tank and crankcase, measurement 43 mm/1.69  
inches)  
• hand grip cover, air filter and cylinder cover  
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Repair instructions  
Starter assembly – removal  
Replacing a broken or worn starter cord  
1
1
Before replacing a worn starter cord the tension in the  
recoil spring must be released. Pull the starter cord out  
through the notch in the pulley rim and wind the pulley  
anti-clockwise to release the tension in the spring.  
Undo the four bolts that fasten the starter assembly  
to the crankcase and lift off the starter assembly.  
2
Remove the bolt from the centre of the pulley and  
lift off the pulley.  
2
3
Pull out about 30 cm of the cord and fasten it in the  
notch in the pulley rim. Release the tension in the  
return spring by letting the pulley wind backwards  
slowly.  
3
WARNING!  
If the recoil spring is still under  
tension when the pulley is re-  
moved it can fly out and cause in-  
jury. Wear eye protection.  
Remove the bolt from the centre of the pulley and  
lift off the pulley.  
Fit a new cord through the hole in the pulley and tie  
a knot to secure it. Feed the other end of the cord  
through the hole in the starter housing and through  
the starter handle, then tie a double knot in the  
end. Wind about 3 turns of the starter cord onto the  
pulley. Fit the bolt through the centre of the pulley  
and tighten to a torque of 2–3 Nm.  
Cleaning and inspection  
Clean the parts and check the following:  
• The starter cord.  
• The teeth on the pulley, lubricate with oil.  
• That the pawls on the flywheel are undamaged,  
i.e. that they spring back towards the centre and  
move freely.  
• Lubricate the return spring with light oil.  
English – 21  
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Repair instructions  
Replacing a worn recoil spring  
WARNING!  
Make sure the recoil spring does  
not fly out and cause injury. Wear  
eye protection.  
1
Remove the bolt from the centre of the pulley and  
lift off the pulley and spring.  
2
Remove the broken recoil spring.  
3
Fit the bolt through the centre of the pulley and  
tighten to a torque of 2–3 Nm.  
Cleaning and inspection:  
• Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the dam-  
aged parts with new ones. Lubricate the return  
spring with light oil.  
Tension the recoil spring, see “Tensioning the recoil  
spring”.  
Starter assembly – refitting  
Tensioning the recoil spring  
1
1
Fasten the starter cord in the notch in the pulley  
rim and wind the pulley about 2 turns clockwise.  
Check that the pulley is free to rotate at least  
another half turn when the starter cord is fully  
extended.  
Position the starter assembly on the crankcase and  
tighten the bolts to a torque of 2.5–3.5 Nm.  
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Repair instructions  
2
Ignition module – testing  
If there is a fault in the ignition system the ignition  
module must be tested before the ignition system  
is removed.  
If replacing the ignition module, disconnect its leads  
and unscrew it. The ignition module can be left in  
place if you are simply removing the flywheel.  
3
Test the ignition module as follows:  
• Connect a test spark plug 502 71 13-01 to the  
ignition lead and clip the test spark plug onto the  
cylinder.  
• Turn the engine over using the starter cord.  
• If the test spark plug produces a spark the  
ignition module is OK.  
Ignition module/flywheel – removal  
Loosen the flywheel nut using a suitable socket and  
unscrew it until it is flush with the end of the shaft.  
1
4
Remove the cylinder cover. Disconnect the HT lead,  
remove the spark plug and fit piston stop 502 54 15-  
01 in its place. Take off the starter assembly, release  
the leads from the cable guide and remove it.  
Position puller 504 90 90-02 over the magnets and  
counterweight on the flywheel. Tighten 2–3 turns  
and tap the head of the puller with a metal mallet to  
release the flywheel. Remove the puller, nut and  
washer. Lift off the flywheel.  
Model 346XP, 351, 353:  
Remove the cover from the hand grip.  
Cleaning and inspection  
• Clean all parts, especially the tapers on the  
flywheel and shaft.  
• Check that the flywheel is not cracked or dam-  
aged in any other way.  
English – 23  
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Repair instructions  
4
Replacing the generator, model 346XP,  
351, 353  
Remove the fuel hose and throttle pushrod from  
the carburettor.  
1
Unbolt the rear tank mounting from the crankcase,  
i.e. the rear vibration damping spring, and both  
stops. Lower the tank as far as it will go to allow  
access to the heater lead where it is connected to  
the tank.  
Remove the cylinder cover. Disconnect the HT lead,  
remove the spark plug and fit piston stop 502 54 15-  
01 in its place. Take off the starter assembly, release  
the leads from the cable guide and remove it.  
Remove the cover from the hand grip.  
5
2
Disconnect the generator lead from the hand grip  
and unclip it from the tank. Remove the generator  
and lead.  
Generator – refitting  
1
Feed the generator lead through the holes in the  
crankcase and hand grip. Bolt the generator in  
position, tightening the bolts to a torque of 5 Nm.  
Clip the lead to the tank.  
NOTE! The lead connector must be positioned on  
the right of the clip, see diagram. Connect the lead  
to the connector on the hand grip.  
2
Loosen the flywheel nut using a suitable socket  
and unscrew it until it is flush with the end of the  
shaft.  
Position puller 504 90 90-02 over the magnets and  
counterweight on the flywheel. Tighten 2–3 turns  
and tap the head of the puller with a metal mallet to  
release the flywheel. Remove the puller, nut and  
washer. Lift off the flywheel.  
Refit:  
• fuel tank with both stops and rear vibration  
damping spring  
• fuel hose to carburettor, hose length between  
tank and crankcase: 43 mm/1.69 inches and  
between crankcase and carburettor: 53 mm/2.09  
inches  
• throttle pushrod to carburettor  
• flywheel with nut and washer  
3
• cable guide, leads and starter assembly  
Remove the piston stop and reconnect the HT lead  
and cylinder cover.  
Unscrew the two bolts from the generator but leave  
the generator in place.  
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Repair instructions  
3
Ignition module and flywheel – refitting  
1
Place the flywheel on the crankshaft. Turn the  
flywheel so that the key lines up with the keyway in  
the shaft.  
Fit the washer and nut on the shaft and tighten to a  
torque of 25-30 Nm.  
Then refit:  
• cable guide and press the leads into position  
• HT lead  
• starter assembly, tighten to a torque of 2.5–3.5  
Nm  
2
• cylinder cover  
0,3 mm  
To refit the ignition module proceed as follows:  
Turn the flywheel so that the magnets are in line  
with the ignition module. Fit the ignition module  
with the plastic feeler gauge (502 51 34-01) held in  
position at the same time, without tightening the  
bolts. Connect the black earth lead to the front  
screw on the ignition module. Adjust the gap  
between the ignition module and magnet to 0.3 +/-  
0.1 mm. The gap must be measured at either of  
the two lowest pegs on the ignition module.  
Tighten the bolts to 4.5–6 Nm. Connect the blue  
lead to the ignition module.  
English – 25  
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Repair instructions  
Inspection and cleaning  
Centrifugal clutch – removal  
1
• Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the dam-  
aged parts with new ones. Always use original  
parts.  
Remove the cylinder cover. Disengage the chain  
brake by pushing the kickback guard backwards.  
Undo the guide bar bolts and remove the clutch  
cover, chain and guide bar.  
2
Min 65mm  
• Check the thickness of the clutch shoes by  
using vernier callipers to measure the diameter  
of the clutch. If the diameter is less than 65 mm  
the clutch assembly must be replaced.  
Disconnect the HT lead. Remove the spark plug  
and fit piston stop 502 54 15-01 in its place.  
Centrifugal clutch – refitting  
3
1
NOTE!  
Handle the clutch springs carefully. If they  
are opened up too much they could  
damage the saw.  
Unbolt the clutch using tool 502 54 16-01 and a  
suitable socket or combination spanner. Turn the  
nut clockwise to remove it.  
4
NOTE!  
Handle the clutch springs carefully. If they  
are opened up too much they could  
damage the saw.  
Insert the clutch springs in the shoes using circlip  
pliers.  
Carefully prise out the clutch springs with a screw-  
driver.  
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Repair instructions  
2
3
D
C
B
A
Unbolt and remove the clutch drum (A), RIM chain  
sprocket (B) if fitted, needle bearing (C) and pump  
drive wheel (D).  
Fit the clutch onto the crankshaft and tighten  
anticlockwise as far as it will go. Then tighten to a  
torque of at least 20 Nm using tool 502 54 16-01  
and a suitable socket or combination spanner.  
Model 350:  
Remove the bolts on the anti-vibration elements on  
the same side.  
3
Remove the piston stop. Fit the spark plug, tightening  
it to a torque of 15 Nm, then connect the HT lead.  
4
Then refit:  
• cylinder cover  
• guide bar  
• chain  
• clutch cover  
Oil pump – removal 346XP, 350, 351,  
353  
1
Empty and clean the oil tank.  
Unbolt the oil pump from the crankcase.  
2
C
5
A
B
D
Remove the cylinder cover. Disengage the chain  
brake by pushing the kickback guard backwards.  
Undo the guide bar bolts and remove the clutch  
cover, chain and guide bar. Disconnect the HT  
lead. Remove the spark plug and fit piston stop  
502 54 15-01 in its place. Unscrew the clutch  
(clockwise) using clutch tool 502 54 16-01 and a  
suitable socket spanner or combination spanner.  
Remove the oil hose and filter (A).  
Model 350:  
Push the housing up a little from the fuel tank and  
remove the filter (A) from underneath, see the  
diagram under “Oil pump – removal 340, 345”.  
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Repair instructions  
6
Oil pump –refitting 346XP, 350, 351, 353  
Remove the pin (B) from the adjuster screw, using  
a small drift to press it out.  
C
1
7
Press in the pump piston (C) so that the adjuster  
screw (D) can be removed. Remove the pump  
piston.  
A
Oil pump – removal 340, 345  
B
D
1-4  
See ”Oil pump – removal, models 346XP, 350,  
351, 353”, points 1-4.  
Remove the bolts on the anti-vibration elements on  
the same side.  
Lubricate the pump piston (C) with chain oil and fit  
the pump piston and washers.  
5
2
Press down the pump piston (C). Fit the adjuster  
screw and spring so that the pin (B) can be  
pressed into position.  
3
Reconnect the oil hose and filter (A).  
Model 350:  
Carefully lift out the oil pump from the crankcase.  
Push the crankcase up a little from the fuel tank  
and screw on the filter (A) from underneath.  
6
WARNING!  
Poor chain lubrication can result  
in failure of the chain, which could  
cause serious or fatal injury.  
4
Push the crankcase up a little from the fuel tank  
and remove the filter (A) from underneath.  
Cleaning and inspection  
Bolt the oil pump to the crankcase. The adjustable  
oil pump must be bolted to torque of 2–3 Nm.  
• Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the damaged  
parts with new ones. Always use original parts.  
• Lubricate all moving parts with chain oil.  
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Repair instructions  
5
Oil pump –refitting 340, 345  
1
Lubricate the piston pump (C) with chain oil and fit  
the pump piston.  
2
Fit the pump. A round pin secures its position.  
Fit the chain guard plate, tightening the bolts to a  
torque of 2–3 Nm.  
Model 350:  
Fit the bolts on the anti-vibration elements on the  
same side.  
6
D
C
B
A
Push the crankcase up a little from the fuel tank  
and screw on the filter (A) from underneath.  
3
Fit the chain guide plate (one bolt), tightening  
torque 2-3 Nm.  
NOTE! Check that the chain tensioner is in posi-  
tion. Fit the bolts on the anti-vibration elements.  
Note.  
Models 340 and 345 have another type of chain  
tensioner, which is adjusted from the side.  
Lubricate the needle bearing with grease. Fit the  
pump drive wheel (D), needle bearing (C), chain  
sprocket (B), if fitted, and clutch drum (A).  
7
4
Fit the clutch onto the crankshaft and tighten  
anticlockwise as far as it will go. Then tighten to a  
torque of at least 20 Nm using tool 502 54 16-01  
and a suitable socket spanner or combination  
spanner.  
See ”Oil pump – Refitting, models 346XP, 350,  
351, 353” pos. 6-9.  
8
Remove the piston stop. Fit the spark plug, tighten-  
ing it to a torque of 15 Nm, then connect the HT  
lead. Then refit the cylinder cover, guide bar, chain  
and clutch cover.  
9
Refill the tank with oil. For more information see  
the user instructions for this model for the recom-  
mended grade of oil.  
English – 29  
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Repair instructions  
2
Adjustable oil pump – adjustment  
A
346XP, 350, 351, 353  
Use a screwdriver or adjustable spanner to turn the  
adjuster screw on the pump. Turning the screw  
clockwise decreases the oil flow and turning it anti-  
clockwise increases the oil flow.  
C
B
Disconnect the pushrod from the carburettor by  
first carefully prising up the spring over the end of  
the rod, where it connects to the throttle lever (A).  
Then press the throttle lever forwards (B) while  
pressing the throttle pushrod backwards (C) and  
lifting it off the lever. Withdraw the throttle pushrod  
from the tank and lift it upwards without pulling it  
through the rubber inlet manifold. Carefully release  
the carburettor assembly from the right-hand  
rubber mounting and lift it upwards.  
+
–
1
2
3
Recommended setting:  
13–15" bar Min. setting  
15–18" bar Midway setting  
18–20" bar Max. setting  
3
Carburettor – removal  
1
Open the spring lock on the rubber bellows.  
4
NOTE!  
Do not use knurled pliers to disconnect or  
reconnect the fuel hose. This could  
damage the hose and lead to leakage or  
fracture.  
Remove the cylinder and air filter. Disconnect the  
leads from the stop switch and the fuel hose from  
the carburettor.  
Undo and remove the carburettor bolts. Lift off the  
carburettor.  
30 – English  
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Repair instructions  
On saws with a carburettor heater 346XPG,  
Carburettor – dismantling  
351G, 353G  
Heating element  
Remove the bracket’s two bolts above the carbu-  
rettor. Disconnect the cable connections to the  
carburettor heater and remove the heating ele-  
ment.  
O
O
Z
Z
5
N
5
N
F
G
The item numbers in the diagram refer to the steps  
below (1–7).  
3
F
G
3
K
V
X
1
K
V
X
Remove the cover from the metering unit and  
carefully remove the metering diaphragm and  
gasket.  
4
4
2
Undo the screw and take out the needle valve,  
together with the lever arm, spindle and spring.  
3
1
Y
Remove the cover from the pump unit and carefully  
remove the gasket and pump diaphragm.  
1
Y
H
H
4
Remove the fuel filter.  
When replacing the thermostat: Disconnect the  
cable from X and V. Trouble shooting, see page  
20.  
5
Remove the high, low and idling jet screws. (HDA  
159A high and low jet screws are protected by  
plastic caps which can be prised off with a screw-  
driver. Only on EPA, see appendix A.)  
On saws with carburettor 346XPG, 351G, 353G  
Replacing the heating element: Lower the rear  
section of the tank by removing the bolt between  
the hand grip cover and vibration damping springs.  
Remove the starter and then loosen the stop  
screws on both sides (one is located under the  
starter and this must be removed first). Now  
disconnect the cable from X and Y.  
6
Remove the plug by first drilling a hole in it and  
then prising it out with a screwdriver or the like.  
7
If necessary remove the throttle and choke valves,  
and remove the spindles together with the lever  
arms and springs.  
Dismantling the carburettor: Loosen the high, low  
and idling jet screws.  
English – 31  
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Repair instructions  
1
Cleaning and inspection  
If the throttle and choke butterflies and their  
spindles were removed, these must be refitted.  
Lubricate the spindle bearings with light oil.  
Clean all the carburettor components in petrol. Use  
an airline to dry off the petrol from all components.  
Blow through all the channels in the carburettor  
body and check that they are not blocked.  
2
Insert the plug in the hole with the convex side  
upwards and expand it by pressing downwards  
with a drift.  
Check that:  
• The gasket, pump diaphragm and metering  
diaphragm are undamaged.  
3
• There is no play in the throttle and choke valves.  
Refit the high and low speed jet screws and  
springs, plus the idling screw. Fit the plastic caps  
over the high and low speed screws.  
4
Fit the fuel filter, using the handle of a small screw-  
driver.  
• The needle valve and its lever arm are not worn.  
• The fuel filter is undamaged.  
5
• The tips of the high and low speed jet screws  
are not damaged.  
Fit the pump diaphragm, gasket and cover to the  
pump unit.  
• The air intake duct is not cracked.  
6
Carburettor – reassembly  
NOTE!  
Cleanliness is very important when  
reassembling the carburettor. Tiny parti-  
cles of dirt can cause operating problems.  
Fit the needle valve with lever arm, spindle and  
spring and tighten the screw.  
Use a rule to check that the lever arm is level with  
the cover face. If necessary, the lever arm can be  
bent slightly.  
7
Fit the metering diaphragm with its gasket and refit  
the cover to the metering unit.  
8
Carry out pressure testing.  
The item numbers in the diagram refer to the steps  
below (1–8).  
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Repair instructions  
Carburettor – pressure testing  
Carburettor – refitting  
Pressure testing should be carried out with the  
carburettor fully assembled. Testing should always  
be carried out after the carburettor has been  
repaired, but can also be performed for trouble-  
shooting before dismantling.  
NOTE!  
Cleanliness is very important when reas-  
sembling the carburettor. Tiny particles of  
dirt can cause operating problems.  
Carry out the test as follows:  
1
• Screw in the high and low speed jet screws and  
back them off one turn.  
• Connect pressure tester 502 50 38-01 to the  
carburettor fuel inlet.  
Fit stop plate 502 54 17-01 between the carburet-  
tor flange and the insulating plate.  
• Lower the carburettor into a beaker of water.  
On saws with a carburettor heater  
346XPG, 351G, 353G  
• Pump up the pressure to 50 kPa (0.5 bar) and  
clamp the pump tube.  
• There should be no leakage. If leakage occurs,  
refer to the table below.  
Leakage  
Fault lies in  
Diffuser jets  
Needle valve  
In impulse tube  
Ventilation hole above  
metering unit  
Pump diaphragm  
Control diaphragm  
Insert the heating element between the air filter  
connection and carburettor as well as above the  
carburettor. Route the cable as illustrated above.  
Tighten the bracket above the carburettor with the  
two bolts.  
Connect the cables to the carburettor heater.  
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Repair instructions  
5
2
Connect the leads to the stop switch.  
Carburettor heater 346XP, 351, 353 –  
Refitting  
Fit the carburettor. Screw in the carburettor bolts  
directly from behind, without lifting the carburettor  
assembly. Tighten to a torque of 1–1.5 Nm. It is  
important to hold the carburettor flange while  
tightening the bolts to prevent the inlet manifold  
from moving.  
Heating element  
3
1
Push the rear carburettor mounting into its rubber  
bushing using a small screwdriver. Remove stop  
plate 502 54 17-01.  
Fit the heating element between the air filter  
connection and the carburettor as well as above  
the carburettor.  
4
2
Tighten the bracket above the carburettor using the  
two bolts.  
3
Connect the leads to the carburettor heater.  
Refit:  
• carburettor  
Connect the fuel hose to the carburettor. Refit the  
throttle pushrod at the same time as the rubber  
inlet manifold, press in the throttle pushrod so that  
it engages in the carburettor and fit the spring.  
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Repair instructions  
4
Air intake system – removal  
The air intake system comprises:  
• inlet manifold  
• insulating plate with clip  
• carburettor flange  
• impulse hose  
• support ring  
1
Unscrew the four cylinder bolts. Lift up the cylinder  
so that the intake system insulating plate is free of  
the crankcase.  
Remove:  
• cylinder cover  
• air filter  
• carburettor  
• HT lead  
• starter assembly (340, 345)  
• Fuel tank (340, 345)  
2
On models 340 and 345 there are cylinder bolts on  
the underside.  
5
Unbolt the vibration damping spring between the  
cylinder and hand grip.  
3
Free the insulating plate from the cylinder by  
releasing the clamp using pliers. Remove the  
complete air intake system.  
6
Remove:  
• support ring  
• carburettor flange from the inlet manifold  
• insulating plate  
Cleaning and inspection  
Clean and inspect all parts carefully. If there are  
any cracks or other defects replace the damaged  
parts with new ones. Always use original parts.  
NOTE! When replacing the impulse hose it must  
not be lubricated with oil or grease.  
Unscrew and remove the bolt from the silencer  
support.  
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Repair instructions  
4
Air intake system – refitting  
1
A
B
Fit the inlet manifold (A) through the insulating  
plate in the carburettor flange cut-out (B), and  
check that the insulating plate’s impulse tube sits  
correctly in the inlet manifold. Fit the perforated  
brass support ring in the inlet manifold.  
Refit the carburettor. Screw in the carburettor bolts  
directly from behind without lifting the carburettor  
assembly, tightening to a torque of 1–1.5 Nm. It is  
important to hold the carburettor flange securely  
when tightening the bolts to prevent the inlet  
manifold from moving.  
2
4
Fit the air intake system on the cylinder and snap  
the insulating plate into position. Check carefully  
that the impulse tube is correctly seated against  
the cylinder’s impulse channel.  
Push down the rear carburettor mounting into the  
rubber bushings using a small screwdriver. Re-  
move tool 502 54 17-01.  
3
5
Refit:  
• cylinder, see special instructions  
• silencer support (does not apply to 340, 345,  
350)  
• air filter  
• HT lead  
• cylinder cover  
• after the test run retighten the silencer bolts to a  
torque of 8–10 Nm  
Position tool 502 54 17-01 between the carburettor  
flange and the insulating plate.  
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Repair instructions  
If it is not possible to check the maximum speed  
with a tachometer then the H jet should not be set  
to a weaker mixture than the basic factory setting.  
Carburettor – adjustment  
For instructions on adjusting the EPA carburettor  
see appendix A.  
The recommended maximum speed must not be  
exceeded.  
Adjusting the carburettor involves adjusting the  
engine to the local conditions e.g. climate, alti-  
tude, fuel and type of two-stroke oil.  
NOTE!  
The carburettor is equipped with three adjustment  
options.  
If the chain turns at idling speed, the T  
screw should be turned anti-clockwise  
until the chain stops.  
L = Low speed jet  
H = High speed jet  
T = Idling adjustment screw  
Fine adjustment  
Once the chainsaw is “run in” the carburettor should  
be readjusted. First adjust the L jet screw, then the  
idling screw T and finally the H jet screw.  
The recommended engine speeds are as follows:  
Model  
Max revs  
Idle revs  
340  
345  
346XP/G  
350  
350 EPA  
351  
12,500 rpm  
12,500 rpm  
14,200 rpm  
13,000 rpm  
13,000 rpm  
13,000 rpm  
13,000 rpm  
2,700 rpm  
2,700 rpm  
2,700 rpm  
2,700 rpm  
2,700 rpm  
2,700 rpm  
2,700 rpm  
The L and H jets adjust the fuel flow to match the  
airflow that the throttle valve opening allows.  
Turning them clockwise makes the fuel/air mixture  
weaker (less fuel in relation to the amount of air)  
and turning them anti-clockwise makes the fuel/air  
mixture richer. A weak mixture increases the  
engine speed and a rich mixture decreases the  
engine speed.  
353  
Basic requirements  
• Before making any adjustments the air filter  
should be clean and the cylinder cover should be  
in place. If the carburettor is adjusted with a dirty  
air filter, the mixture will be too weak next time  
the air filter is cleaned. This can cause serious  
engine damage.  
The T screw controls the throttle position when  
idling. Turning the T screw clockwise gives faster  
idling; turning it anti-clockwise lowers idling  
speed.  
• Carefully screw in the L and H jets fully, then  
back them off 1 turn. The carburettor now has the  
settings H = 1 and L = 1.  
WARNING!  
• Start the chainsaw and allow it to warm up for 10  
minutes.  
The guide bar, chain and clutch  
cover must be fitted before the  
saw is started, otherwise the  
clutch may fly off and cause inju-  
ry.  
• Place the saw on a flat surface so that the guide  
bar is pointing away from you and the guide bar  
and chain are not touching the surface.  
Basic settings and running in  
Low speed jet L  
During testing at the factory the carburettor is  
adjusted to the basic factory settings.  
The factory settings are H = 1 turn and L = 1  
turn.  
• Find the highest idling speed by slowly screwing  
the L screw in and then out again.  
• When the highest speed has been found, screw  
out the L screw 1/8 - 1/4 turn.  
To ensure that engine components receive  
adequate lubrication (running in) the carburet-  
tor should be set to a somewhat richer fuel  
mixture for the chainsaw’s first 3-4 running  
hours. This is done by adjusting the maximum  
speed to 6-700 rpm less than the recom-  
mended maximum speed.  
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Repair instructions  
Fine adjustment of idling speed T  
Fuel tank – removal  
• The idling speed is adjusted using the screw  
marked T.  
WARNING!  
The fuel used in chainsaws is  
harmful if inhaled, may cause  
skin irritation and is highly flam-  
mable.  
• If adjustment is necessary, screw in the idling  
screw T until the chain starts to turn. Then screw it  
out until the chain stops moving.  
• The idling speed is correctly set when the engine  
runs smoothly in all positions and there is a clear  
margin to the speed at which the chain starts to  
move.  
1
Empty the fuel tank.  
2
Remove the following:  
High speed jet H  
• cylinder cover  
• air filter  
• The high speed jet H influences the saw power  
output and engine speed. If the H jet is set too  
weak the saw will over-rev, which could cause  
engine damage.  
• clutch cover  
• chain and guide bar  
• starter assembly  
• cable guide  
• Run the saw at full throttle for about 10 seconds.  
H=1.  
• Then screw out the H screw 1/4 turn. H=1 1/4.  
• Run the saw again at full throttle for about 10  
seconds and listen to the difference in the engine  
note. Repeat this procedure again with the H  
screw screwed out another 1/4 turn. H=1 1/2.  
3
Disconnect the fuel hose from the carburettor.  
4
• You have now run the saw at settings H 0, H =  
+1/4 and H = +1/2 from the factory setting. At full  
throttle the engine will sound different at each  
setting.  
A
C
• The H screw is correctly adjusted when the saw  
“burbles” a little at full throttle without any load.  
B
• If there is a lot of smoke from the silencer and the  
saw does not run smoothly then the setting is too  
rich.  
• Screw in the H screw to the setting that sounds  
right.  
NOTE!  
For optimum adjustment, a tachometer  
should be used. The recommended maxi-  
mum speed should not be exceeded.  
Disconnect the pushrod from the carburettor by  
first carefully prising up the spring over the end of  
the rod, where it connects to the throttle lever (A).  
Then press the throttle lever forwards (B) while  
pressing the throttle pushrod backwards (C) and  
lifting it off the lever. Withdraw the throttle pushrod  
from the tank and lift it upwards without pulling it  
through the rubber inlet manifold.  
Carburettor – correct adjustment  
• When the carburettor is correctly adjusted the saw  
should accelerate without hesitation and the  
engine will burble a little at full throttle without any  
load.  
• The chain must not turn when idling.  
• If the L screw is set too weak this can make the  
saw difficult to start and cause poor acceleration.  
• If the H screw is set too weak the saw will produce  
less power, poor acceleration and there is a risk of  
engine damage.  
• If either the L or H screws are set too rich it will  
cause acceleration problems or too low working  
speed.  
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Repair instructions  
5
Cleaning and inspection  
Carefully check that:  
• there are no leaks from the fuel tank  
• there are no leaks from the tank filler cap  
• the fuel hose is undamaged and free from wear  
• the fuel filter is not clogged  
• the tank vent is not blocked or leaking  
• the vibration damping springs and stops are not  
damaged  
Replacing the fuel filter  
NOTE!  
Do not use knurled pliers to disconnect or  
reconnect the fuel hose. This could  
damage the hose and lead to leakage or  
fracture.  
1
First remove the old fuel filter from the tank unit  
using special tool 502 50 83-01.  
2
Pull the fuel hose out of the tank and pull off the  
filter.  
Unscrew both stops and the three vibration damp-  
ing springs from the flywheel side and clutch side  
of the engine.  
3
Fit the new fuel filter and feed the fuel hose back  
into position.  
6
Replacing the fuel hose  
NOTE!  
Do not use knurled pliers to disconnect or  
reconnect the fuel hose. This could  
damage the hose.  
1
Before replacing the fuel hose, measure the length  
of hose between the crankcase and carburettor  
and between the tank and crankcase. The correct  
hose length between the tank and crankcase is 43  
mm (1.69 inches). The correct hose length be-  
tween the crankcase and carburettor is 53 mm  
(2.09 inches).  
Disconnect and remove the fuel hose from the  
crankcase.  
2
Remove the fuel hose from the fuel tank using tool  
502 50 83-01. Trim off 5 mm (0.20 inches) from the  
mitred end of the hose. Fit the fuel filter and  
reinsert the hose in the tank.  
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Repair instructions  
3
Tank vent – testing  
1
Fit the throttle pushrod in the tank and connect it to  
the carburettor. Refit the spring.  
Connect pressure gauge 502 50 38-01 to the fuel  
hose. Pump the pressure up to 50 kPa (0.5 bar).  
The pressure should drop to 20 kPa (0.2 bar)  
within 60 seconds.  
4
A
C
2
B
Connect the fuel hose to the carburettor. Check  
that the hose is not kinked or too long to be  
clamped between the crankcase and tank. The  
correct hose length between the tank and crank-  
case is 43 mm (1.69 inches). The correct hose  
length between the crankcase and carburettor is  
53 mm (2.09 inches) excluding the mitred section.  
Use gauge 502 50 37-01 to measure vacuum.  
Readings should be as follows: the vacuum should  
increase from 30 to 15 within 30 seconds. If  
readings are outside this range the vyon plugs  
must be replaced.  
5
Fuel tank – refitting  
1
Insert the fuel hose into the carburettor chamber.  
Refit the fuel tank.  
2
Connect the fuel hose to the carburettor.  
6
Then refit:  
• cable guide  
Bolt the front vibration damping spring into posi-  
tion, followed by both stops and the remaining two  
vibration damping springs. Tighten to a torque of  
2–3 Nm. Check that both vibration damping  
springs and the stops are correctly seated on the  
crankcase. Incorrect fitting may result in higher  
vibration levels.  
• starter assembly (2.5–3 Nm)  
• chain and guide bar  
• clutch cover  
• air filter  
• cylinder cover  
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Repair instructions  
4
Piston and cylinder – removal  
Cover the opening in the crankcase.  
1
Remove:  
5
• cylinder cover  
• carburettor (see “Carburettor – removal”)  
• silencer  
• spark plug  
• fuel tank (applies to 340, 345)  
2
Remove the circlips from the ends of the gudgeon  
pin and press it out. Then lift off the piston.  
6
Unbolt the vibration damping spring from the hand  
grip.  
3
Remove the bearing from the little end of the  
connecting rod.  
7
Undo the four cylinder bolts and lift the cylinder off  
carefully.  
Models 340, 345  
If replacing the cylinder:  
Unscrew the decompression valve. Remove the  
intake system, see “Air intake system – removal”.  
Undo the four cylinder bolts from the underside  
and lift the cylinder off carefully.  
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Repair instructions  
8
When replacing the cylinder 340, 345:  
Unscrew the decompression valve. (345)  
Remove the intake system, see “Air intake system  
– removal”.  
• Measure piston ring wear. This should not  
exceed 1 mm. Use the piston to push down the  
piston ring.  
Model 350 is fitted with a spacer, which is secured  
using four bolts from the underside. The spacer  
does not however need to be removed when  
removing the cylinder.  
• The needle roller bearing is undamaged.  
• The inlet manifold is undamaged.  
• Pressure test the decompression valve.  
• Also refer to Jonsered’s Analysis guide for piston  
failures, art. no. 108 07 01-01.  
Decompression valve – pressure  
testing  
1
Cleaning and inspection  
Clean all the components, scraping off all traces of  
old gasket and carbon from the following places:  
• Piston crown  
• Top of the cylinder bore  
• Cylinder exhaust port  
Connect tool 502 50 38-01 to the decompression  
valve.  
• Decompression valve channel (340, 346XP,  
350, 351, 353)  
• Cylinder base and/or crankcase  
2
Pump up the pressure to 80 kPa (0.8 bar).  
Check the following:  
3
• The surface coating of the cylinder is not worn  
through, especially in the upper part of the  
cylinder.  
Wait 30 seconds.  
4
The pressure should not be less than 60 kPa  
(0.6 bar).  
• The cylinder is free from score marks and areas  
of wear.  
• The piston is free from score marks. Small  
scratches can be polished out with fine emery  
paper.  
• The piston ring is not burnt into its groove.  
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Repair instructions  
4
Piston and cylinder – refitting 346XP,  
350, 351, 353  
1
Press the insulating plate 503 86 62-01 onto the  
cylinder. Check that the impulse tube connected to  
the insulating plate is seated correctly in the inlet  
manifold and lock the clamp over the manifold.  
5
Lubricate the little end bearing with two-stroke oil  
and insert it in the connecting rod.  
Lubricate the piston ring and piston with two-stroke  
oil.  
2
6
Fit the piston with the arrow pointing towards the  
exhaust port. Push in the gudgeon pin and fit the  
circlips. If replacing the cylinder, fit the decompres-  
sion valve, tightening to a torque of 12–14 Nm.  
Fit a new cylinder base gasket. Compress the  
piston ring with tool 502 50 70-01 and lower the  
cylinder over it carefully.  
3
7
1
4
Fit the inlet manifold 503 86 63-01 to the cylinder.  
Check that the impulse tube is correctly seated in  
the impulse channel.  
3
2
NOTE!  
It is very important that there are no leaks  
in the inlet system, otherwise the engine  
may seize.  
Fit the cylinder bolts, tightening them in diagonal  
pairs to a torque of 8–10 Nm.  
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Repair instructions  
Piston and cylinder – refitting 340, 345  
Cylinder – pressure testing  
1-5  
See Piston and cylinder 346XP, 350, 351, 353 –  
Refitting points 1-5.  
6
Apply silicone adhesive/sealing compound (03-  
7062) to the crankcase’s contact surfaces with the  
cylinder.  
Carefully slide the cylinder down over the piston  
towards the big end bearing.  
Note!  
Work is facilitated if the crankshaft complete with  
bearing and piston is released from the crankcase  
and the piston is pushed into the cylinder. The unit  
is then refitted in the crankcase.  
7
• Loosen the carburettor bolts so that the carbu-  
rettor can be moved back about 4 mm. Insert  
cover plate 502 54 11-02 between the carburet-  
tor and the carburettor flange. Tighten the  
carburettor bolts to a torque of 1–1.5 Nm.  
• Loosen the silencer bolts so that the silencer  
can be moved back about 4 mm. Insert cover  
plate 502 54 11-02 between the silencer and the  
exhaust flange on the cylinder flange. Tighten  
the silencer bolts to a torque of 8–10 Nm.  
• Unscrew and remove the spark plug. Screw in  
pressure test nipple 503 84 40-02. Connect tool  
502 50 38-01 to the nipple. The decompression  
valve must be closed. The decompression valve  
must be closed. To check the decompression  
valve itself, see “Decompression valve – pres-  
sure testing”.  
Fit the cylinder bolts, tightening crosswise to a  
torque of 13–15 Nm.  
8
Pressure test the cylinder.  
• Pump up the pressure to 80 kPa (0.8 bar).  
• Wait 30 seconds.  
9
Refit:  
• The pressure should not be less than 60 kPa  
(0.6 bar).  
• spark plug, tighten to a torque of 15 Nm  
• carburettor, see “Carburettor – refitting”,  
• silencer, tighten to a torque of 8–10 Nm  
• cylinder cover  
• Remove the cover plates from the silencer and  
carburettor, tighten the bolts to the specified  
torque. Remove the pressure test nipple 503 84  
40-02 and refit the spark plug.  
WARNING!  
After pressure testing the cylin-  
der, check that the inlet manifold  
is seated correctly, otherwise the  
saw may be damaged.  
NOTE!  
If a new piston or cylinder has been fitted  
the saw must be run for the first 3–4  
hours with carburettor adjusted to the  
factory settings.  
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Repair instructions  
3
Crankcase and crankshaft –  
dismantling 346XP, 351, 353  
1
Remove the following:  
• guide bar and chain  
• clutch cover  
• cylinder cover  
• starter assembly*  
• ignition system*  
• generator*  
• centrifugal clutch*  
• oil pump*  
Split the crankcase with the aid of tool 502 51 61-  
01 (A) and stop plate 502 54 18-01 (B), working  
from the flywheel side of the saw.  
• bark rest  
• chain tensioner  
• throttle pushrod  
• carburettor*  
4
• carburettor base  
• silencer*  
• piston and cylinder*  
• fuel tank*  
* See special instructions.  
NOTE!  
Take care to prevent dirt or foreign parti-  
cles getting into the bearings.  
2
Press the crankshaft out of the flywheel side of the  
crankcase using tool 502 51 61-01.  
5
Do the same on the clutch side without using stop  
plate 502 54 18-01.  
Unscrew the 6 bolts that hold the crankcase  
together.  
English – 45  
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Repair instructions  
Crankshaft complete - dismantling  
340, 345, 350  
Crankshaft bearings – replacement  
346XP, 351, 353  
If the crankshaft bearings are to be replaced, tap  
them out gently using drift 502 70 84-01.  
1
Remove the following:  
• chain and bar  
• clutch cover  
• cylinder cover  
• starter assembly*  
• ignition system*  
• generator  
• centrifugal clutch*  
• throttle pushrod  
• carburettor*  
The new bearings must be shrunk-fit into the  
crankcase using a hot air gun.  
Cleaning and inspection  
• silencer*  
Clean and inspect all parts carefully.  
• piston and cylinder*  
• fuel tank*  
Sealing ring – replacement  
Remove the sealing ring from the magnet side  
using tool 502 50 55-01.  
* See special instructions.  
2
Sealing ring replacement - drive side  
Remove the oil pump.  
1
Lift the crankshaft completely out of the crankcase.  
350:  
Unbolt the four bolts from underneath and lift off  
the spacer.  
Lift the crankshaft completely out of the crankcase.  
Pry up the sealing ring from the bearing by using a  
small screwdriver or the like.  
Note. The sealing ring can be replaced without the  
need of removing the bearing.  
2
Press the new sealing ring into the bearing.  
46 – English  
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Repair instructions  
Crankcase and crankshaft –  
reassembly 346XP, 351, 353  
Cleaning and inspection  
Clean and inspect all parts carefully.  
1
Sealing ring – replacement  
Remove the sealing ring from the crankcase using  
a small screwdriver.  
NOTE!  
Take care to avoid damaging the crank-  
case.  
Hold the clutch side of the crankcase in a vice. Pull  
the crankshaft into its bearing using assembly tools  
502 70 84-01 and 502 70 45-07.  
To fit the sealing ring use the sleeve that is sup-  
plied with 502 50 30-16.  
The end with the half moon is used for the sealing  
ring on the clutch side, which must be fitted flush  
with the surface of the crankcase.  
2
The other end of the sleeve is used to fit the  
sealing ring on the flywheel side and ensures that  
the sleeve is fitted at the correct depth, 1.8 mm.  
Lubricate the sealing rings with oil.  
Crankshaft bearings 340, 345, 350 –  
replacement  
Check that the guide pins are in place. Fit a new  
gasket to the mating surface of the clutch side of  
the crankcase.  
Remove:  
3
• The crankshaft complete from the crankcase,  
see page 47.  
1
Pull off the crankshaft bearing from crankshaft.  
Place the flywheel side of the crankcase over the  
crankshaft and pull the two crankcase halves  
together using assembly tools 502 70 84-01 and  
502 70 45-06.  
2
Fit a new bearing on the crankshaft.  
English – 47  
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Repair instructions  
4
Crankshaft complete 340, 345, 350 –  
reassembly  
Fit and tighten the six crankcase bolts to a torque  
of 8–10 Nm. Check that the crankshaft rotates  
freely.  
1
5
Fit the crankshaft complete in the crankcase.  
Refit the following parts:  
350:  
• bark rest  
Fit and tighten the four bolts holding the spacer  
from underneath and fit the crankshaft complete in  
the crankcase.  
• oil pump*  
• chain tensioner  
• centrifugal clutch*  
• fuel tank*  
Refit the following parts:  
• piston and cylinder*  
• fuel tank*  
• piston and cylinder*  
• generator*  
• silencer*  
• carburettor base  
• carburettor*  
• carburettor*  
• throttle pushrod  
• centrifugal clutch*  
• generator*  
• throttle pushrod  
• silencer*  
• ignition system*  
• starter assembly*  
• cylinder cover  
• clutch cover  
• ignition system*  
• starter assembly*  
• cylinder cover  
• clutch cover  
• guide bar and chain  
* See special instructions.  
• chain and bar  
* See special instructions.  
NOTE!  
If a new crankshaft has been fitted the  
saw must be run in for 3-4 hours with the  
carburettor adjusted to the factory set-  
tings.  
48 – English  
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Repair instructions  
Guide bar bolts – replacement  
Repairing damaged threads  
1
A repair kit, 503 27 33-01, is available for repairing  
damaged threads.  
Drain the oil tank.  
2
First drill out the hole using:  
Knock through the old guide bar bolt so that it falls  
6.1 mm drill bit for magnesium crankcase  
into the oil tank.  
Then screw in the thread insert using a suitable  
bolt and spanner.  
3
Remove the bolt from the oil tank.  
4
Thread insert  
Fasten a steel wire to the thread of the new bolt,  
feed the steel wire into the oil tank and out through  
the bolt hole in the crankcase.  
A damaged thread can be repaired using a thread  
insert. The slotted part of the thread insert is  
screwed in first, as this is the cutting part.  
5
Pull the steel wire until the bolt comes out through  
its hole.  
To repair a thread that was originally designed for a  
PL5 screw: first drill out with a 6.1 mm diameter  
drill bit, then screw in the thread insert using a  
suitable screw and spanner.  
6
Pull through the bolt with its nut. Place a spacer  
between the nut and crankcase.  
To repair a thread that was originally designed for a  
MT6 screw: first drill out with a 7.1 mm diameter  
drill bit, then screw in the thread insert using a  
suitable screw and spanner.  
7
Check that the square shoulder of the bolt is  
correctly seated in the recess in the crankcase.  
This type of thread insert is best suited for use in  
plastic and magnesium, but not for repairing  
threads in aluminium. In that case use a helicoil  
insert with metric screw.  
8
Refill with chain oil.  
New part no.  
503 27 39-01  
503 27 40-01  
Description  
PL5  
MT6  
English – 49  
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Repair instructions  
Appendix A  
5. Let the engine run at ”B” rpm ~ 1 minute, until warm.  
6. Adjust the H-needle to a top speed of ”C” rpm.  
Model  
Basic adjustment for EPA II carburetors  
After replacing the carburetor or high speed and/or low  
speed needle on an EPA (The US Environmental  
Protection Agency) certified product a basic adjustment  
must be carried out as described below in order to meet  
the EPA-requirements. This to achieve as low emissions  
as possible. This instruction is made for USA & Canada  
only. On EPA carburetors both the H- and L-needles are  
fitted with caps to prevent the chain saw operator from  
changing the adjustment above EPA standard. The caps  
can be removed to achieve richer or leaner adjustments.  
To set the needles correctly an adjustment sleeve is fitted  
from the factory over the caps to lock them in maximum  
allowed settings.  
340/345/350/351  
346XP  
C = 13 700  
C = 14 300  
7. Check that the H-cap is still adjusted to its richest  
setting. (Turned counterclockwise to stop). NOTE!  
The H-needle must not rotate!  
8. Gently knock the H-cap into position. Use a 5 mm/0.2  
inch mandrel (for ex. the locking pin for the bevel gear  
ref.no. 502 02 61-03). This is a basic carburetor  
adjustment. Further fine adjustments, within the limits  
the caps allow, may be necessary to achieve optimum  
performance. See the Operator’s manual.  
When correctly set the caps must be fixed on the nee-  
dles. The adjustment sleeve then can be removed. Over  
the caps on complete sparepart carburetor, there is a  
plastic sleeve which is intended to lock the caps at the  
richest position (anticlockwise towards stop) during the  
time that the needles are adjusted. When the adjustment  
is complete and the caps have been fixed on the nee-  
dles, the sleeve is no longer of any function and can be  
removed.  
Replacement of the L-needle  
1. Take off the cap from the L-needle using e.g. a pair of  
cutting pliers and unscrew the needle.  
2. Screw the new L-needle to the bottom and then turn it  
counterclockwise ”D” turns.  
Model  
340/345/350  
346XP/351  
D = 1 1/2  
D = 1 1/2  
NOTE! On the complete spare part carburetor, the L-  
needle is adjusted from the factory.  
3. Press a new L-cap on the L-needle to the first stop,  
which means that the cap is not fixed to the needle, it  
should rotate independently.  
NOTE! Before making any adjustments the following  
must be done!  
• Mount, for this model, approved bar & chain combina-  
tion (See Technical data in the Operator’s manual).  
4. Adjust the L-cap to the richest position (turned  
counterclockwise to stop) without turning the needle.  
Model  
340/345/350  
346XP/351  
5. Let the engine run at ~ ”E” app.1 minute until warm  
and then let it run on idle.  
16”  
16”  
Model  
• The chain should not be tensioned more than that it  
remains ~0,2 inches to the bar.  
340/345/350/351  
346XP  
E = 12 000  
E = 13 000  
• Mount a new air filter.  
6. Adjust the idle speed to ”F” rpm.  
Model  
Replacement of the H-needle or complete carburetor  
1. Screw the new H-needle to the bottom and turn it  
counterclockwise ”A” turns.  
340/345/350  
346XP/351  
F = 2 700  
F = 2 700  
Model  
340/345/350  
346XP/351  
7. Adjust the L- needle until the highest possible idling  
speed is achieved and then turn the  
A = 3/4  
A = 3/4  
L-needle 1/2 turn counterclockwise. Use a narrow  
blade screwdriver w. ref.no. 531 00 48-63 and insert  
through the hole in the cap (max. blade width 2 mm/  
0.08 inch) .  
2. Check that:  
The H-cap is adjusted to its richest setting. (Turned  
counterclockwise to stop). The cap is not fixed to the  
needle, it should rotate independently. Adjust the L-cap  
to a center position (1/4 turn counterclockwise =  
minimum, 1/4 turn clockwise = maximum).  
NOTE! If the chain rotates, turn the idling speed  
screw (T) counterclockwise until the chain stops.  
8. Check that the L-cap is still adjusted to its richest  
position. (Turned counterclockwise to stop).  
3. Start the engine. If necessary, adjust the idling speed  
with the T-screw until the chain stops.  
NOTE! The L-needle must not rotate!  
4. Adjust the H-needle to give a top speed of ”B” rpm.  
Model  
340/345/350/351  
346XP  
9. Gently knock the L-cap into position. Use a 5 mm/0.2  
inch mandrel (for ex. the locking pin for the bevel gear  
ref.no. 502 02 61-03).  
B = 12 000  
B = 13 000  
This is a basic carburetor adjustment. Further fine  
adjustments, within the limits the caps allow, may be  
necessary to achieve optimum performance. See the  
Operator’s manual.  
Use a narrow blade screwdriver (Ref.no. 531 00 48-63)  
and insert it through the hole in the cap (max. blade width  
2 mm/0.08 inch).  
50 – English  
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114 01 47-26  
2003W12  
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