Owner’s Manual
GX270・GX390
LPG-Fueled Engine
2003 Honda Motor Co., Ltd. -All Rights Reserved
The engine exhaust from this product
contains chemicals known to the State
of California to cause cancer, birth
defects or other reproductive harm.
Keep this owner’s manual handy, so you can refer to it at any time.
This owner’s manual is considered a permanent part of the engine and
should remain with the engine if resold.
The information and specifications included in this publication were in
effect at the time of approval for printing. Illustrations are based on the
GX270 LPG. Honda Motor Co., Ltd. reserves the right, however, to
discontinue or change specifications or design at any time without
notice and without incurring any obligation whatever. No part of this
publication may be reproduced without written permission.
INTRODUCTION
Congratulations on your selection of a Honda engine. We are certain
you will be pleased with your purchase of one of the finest engines on
the market.
We want to help you get the best results from your new engine and to
operate it safely. This manual contains the information on how to do
that; please read it carefully.
As you read this manual, you will find information preceded by a
symbol. That information is intended to help you avoid
damage to your engine, other property, or the environment.
We suggest you read the warranty policy to fully understand its
coverage and your responsibilities of ownership. The warranty policy
is a separate document that should have been given to you by your
dealer.
When your engine needs scheduled maintenance, keep in mind that
your Honda servicing dealer is specially trained in servicing Honda
engines. Your Honda servicing dealer is dedicated to your satisfaction
and will be pleased to answer your questions and concerns.
Best Wishes,
Honda Motor Co., Ltd.
1
INTRODUCTION
A FEW WORDS ABOUT SAFETY
Your safety and the safety of others are very important. And using this
engine safely is an important responsibility.
To help you make informed decisions about safety, we have provided
operating procedures and other information on labels and in this
manual. This information alerts you to potential hazards that could
hurt you or others.
Of course, it is not practical or possible to warn you about all the
hazards associated with operating or maintaining an engine. You must
use your own good judgment.
You will find important safety information in a variety of forms,
including:
Safety Labels –– on the engine.
Safety Messages –– preceded by a safety alert symbol
of three signal words, DANGER, WARNING, or CAUTION.
and one
These signal words mean:
You WILL be KILLED or SERIOUSLY HURT if
you don’t follow instructions.
You CAN be KILLED or SERIOUSLY HURT if
you don’t follow instructions.
You CAN be HURT if you don’t follow
instructions.
Safety Headings –– such as IMPORTANT SAFETY INFORMATION.
Safety Section –– such as ENGINE SAFETY.
Instructions –– how to use this engine correctly and safely.
This entire book is filled with important safety information –– please
read it carefully.
2
CONTENTS
ENGINE SAFETY ........................................................................................ 5
IMPORTANT SAFETY INFORMATION ................................................. 5
CONTROLS & FEATURES ......................................................................... 7
COMPONENT & CONTROL LOCATIONS ............................................. 7
CONTROLS ............................................................................................. 8
Engine Switch ..................................................................................... 8
Choke Lever ........................................................................................ 9
Throttle Lever ................................................................................... 10
Recoil Starter Grip ............................................................................ 10
FEATURES ............................................................................................ 11
Oil Alert System (applicable engine types) .................................. 11
BEFORE OPERATION .............................................................................. 12
IS YOUR ENGINE READY TO GO? ...................................................... 12
Check the General Condition of the Engine ................................... 12
Check the Engine .............................................................................. 13
Check the Equipment Powered by This Engine ............................. 13
OPERATION ............................................................................................. 14
SAFE OPERATING PRECAUTIONS .................................................... 14
STARTING THE ENGINE ..................................................................... 14
STOPPING THE ENGINE ..................................................................... 18
SETTING ENGINE SPEED .................................................................... 19
SERVICING YOUR HONDA ENGINE ...................................................... 20
THE IMPORTANCE OF MAINTENANCE ............................................. 20
MAINTENANCE SAFETY ..................................................................... 21
MAINTENANCE SCHEDULE ............................................................... 22
FUEL RECOMMENDATIONS .............................................................. 23
ENGINE OIL LEVEL CHECK ................................................................. 24
ENGINE OIL CHANGE .......................................................................... 25
ENGINE OIL RECOMMENDATIONS ................................................... 26
AIR FILTER INSPECTION ..................................................................... 27
AIR CLEANER SERVICE ....................................................................... 28
SPARK PLUG SERVICE ........................................................................ 30
IDLE SPEED ADJUSTMENT ................................................................ 31
SPARK ARRESTER SERVICE (optional part) ...................................... 32
3
CONTENTS
HELPFUL TIPS & SUGGESTIONS .......................................................... 33
STORING YOUR ENGINE .................................................................... 33
Storage Preparation ......................................................................... 33
Storage Precautions ......................................................................... 34
Removal From Storage .................................................................... 35
TRANSPORTING .................................................................................. 36
TAKING CARE OF UNEXPECTED PROBLEMS ...................................... 37
ENGINE WILL NOT START .................................................................. 37
ENGINE LACKS POWER ...................................................................... 37
TECHNICAL & CONSUMER INFORMATION ......................................... 38
TECHNICAL INFORMATION ................................................................ 38
Serial Number Location ................................................................... 38
Remote Control Linkage .................................................................. 39
Carburetor Modification for High Altitude Operation.................... 40
Emission Control System Information ........................................... 41
Air Index ............................................................................................ 43
Specifications ................................................................................... 44
Wiring Diagram ................................................................................ 45
CONSUMER INFORMATION ............................................................... 46
Honda Publications .......................................................................... 46
Warranty Service Information ......................................................... 47
QUICK REFERENCE INFORMATION ............................. Inside back cover
4
ENGINE SAFETY
IMPORTANT SAFETY INFORMATION
Most accidents with engines can be prevented if you follow all
instructions in this manual and on the engine. Some of the most
common hazards are discussed below, along with the best way to
protect yourself and others.
Owner Responsibilities
Honda engines are designed to give safe and dependable service if
operated according to instructions. Read and understand this
owner’s manual before operating the engine. Failure to do so could
result in personal injury or equipment damage.
Know how to stop the engine quickly, and understand the operation
of all controls. Never permit anyone to operate the engine without
proper instructions.
Do not allow children to operate the engine. Keep children and pets
away from the area of operation.
Refuel With Care
LPG is extremely flammable, and LPG can explode. Refuel outdoors, in
a well-ventilated area, with the engine stopped. Never smoke near LPG,
and keep other flames and sparks away.
Hot Exhaust
The muffler becomes very hot during operation and remains hot for
a while after stopping the engine. Be careful not to touch the muffler
while it is hot. Let the engine cool before storing it indoors.
To prevent fire hazards and to provide adequate ventilation for
stationary equipment applications, keep the engine at least 3 feet (1
meter) away from building walls and other equipment during
operation. Do not place flammable objects close to the engine.
5
ENGINE SAFETY
Carbon Monoxide Hazard
Exhaust gas contains poisonous carbon monoxide. Avoid inhalation of
exhaust gas. Never run the engine in a closed garage or confined area.
Other Equipment
Review the instructions provided with the equipment powered by this
engine for any additional safety precautions that should be observed
in conjunction with engine startup, shutdown, or operation, or
protective apparel that may be needed to operate the equipment.
6
CONTROLS & FEATURES
COMPONENT & CONTROL LOCATIONS
MUFFLER
AIR CLEANER
THROTTLE LEVER
SPARK PLUG
CHOKE LEVER
STARTER GRIP
RECOIL STARTER
ENGINE SWITCH
OIL DRAIN PLUG
OIL FILLER CAP
7
CONTROLS & FEATURES
CONTROLS
Engine Switch
The engine switch enables and disables the ignition system.
The engine switch must be in the ON position for the engine to run.
Turning the engine switch to the OFF position stops the engine.
ENGINE SWITCH
OFF
ON
8
CONTROLS & FEATURES
Choke Lever
The choke lever opens and closes the choke valve in the carburetor.
The CLOSED position creates a vacuum to help the LPG to flow into
the engine during starting.
The OPEN position removes the vacuum after the engine has started
and can produced its own vacuum.
Some engine applications use a remotely-mounted choke control
rather than the engine-mounted choke lever shown here.
CHOKE LEVER
CLOSED
OPEN
9
CONTROLS & FEATURES
Throttle Lever
The throttle lever controls engine speed.
Moving the throttle lever in the directions shown makes the engine
run faster or slower.
Some engine applications use a remotely-mounted throttle control
rather than the engine-mounted throttle lever shown here.
THROTTLE LEVER
FAST
SLOW
Recoil Starter Grip
Pulling the starter grip operates the recoil starter to crank the engine.
STARTER GRIP
10
CONTROLS & FEATURES
FEATURES
Oil Alert System (applicable engine types)
The Oil Alert system is designed to prevent engine damage caused
by an insufficient amount of oil in the crankcase. Before the oil level in
the crankcase can fall below a safe limit, the Oil Alert system will
automatically stop the engine (the ignition switch will remain in the
ON position).
If the engine stops and will not restart, check the engine oil level (page
24) before troubleshooting in other areas.
11
BEFORE OPERATION
IS YOUR ENGINE READY TO GO?
For your safety, and to maximize the service life of your equipment, it
is very important to take a few moments before you operate the
engine to check its condition. Be sure to take care of any problem you
find, or have your servicing dealer correct it, before you operate the
engine.
Improperly maintaining this engine,
or failing to correct a problem
before operation, could cause a
malfunction in which you could be
seriously injured.
Always perform a preoperation
inspection before each operation,
and correct any problem.
Before beginning your preoperation checks, be sure the engine is level
and the engine switch is in the OFF position.
Check the General Condition of the Engine
Look and smell around and underneath the engine for signs of oil or
LPG leaks.
Remove any excessive dirt or debris, especially around the muffler
and recoil starter.
Look for signs of damage.
Check that all shields and covers are in place, and all nuts, bolts, and
screws are tightened.
12
BEFORE OPERATION
Check the Engine
Check the engine oil level (see page 24). Running the engine with a
low oil level can cause engine damage.
The Oil Alert system (applicable engine types) will automatically
stop the engine before the oil level falls below safe limits. However,
to avoid the inconvenience of an unexpected shutdown, always
check the engine oil level before startup.
Check the air filter (see page 27 ). A dirty air filter will restrict air flow
to the carburetor, reducing engine performance.
Check the Equipment Powered by This Engine
Review the instructions provided with the equipment powered by this
engine for any precautions and procedures that should be followed
before engine startup.
13
OPERATION
SAFE OPERATING PRECAUTIONS
Before operating the engine for the first time, please review the
IMPORTANT SAFETY INFORMATION on page 5 and the chapter titled
BEFORE OPERATION.
Carbon monoxide gas is toxic.
Breathing it can cause
unconsciousness and even kill you.
Avoid any areas or actions that
expose you to carbon monoxide.
Review the instructions provided with the equipment powered by this
engine for any safety precautions that should be observed in
conjunction with engine startup, shutdown, or operation.
STARTING THE ENGINE
1.Turn the fuel valve to the OPEN or ON position at the source before
attempting to start the engine.
14
OPERATION
2. Move the choke lever to the CLOSED position.
Always use the choke when starting the engine.
Some engine applications use a remotely-mounted choke control
rather than the engine-mounted choke lever shown here.
CHOKE LEVER
CLOSED
3. Move the throttle lever away from the SLOW position, about 1/3 of
the way toward the FAST position.
Some engine applications use a remotely-mounted throttle control
rather than the engine-mounted throttle lever shown here.
THROTTLE LEVER
SLOW
15
OPERATION
4. Turn the engine switch to the ON position.
ENGINE SWITCH
ON
5. Operate the starter.
Pull the starter grip lightly until you feel resistance, then pull briskly.
Return the starter grip gently.
STARTER GRIP
16
OPERATION
6. Move the choke lever to the OPEN position after the engine has
started.
CHOKE LEVER
OPEN
17
OPERATION
STOPPING THE ENGINE
To stop the engine in an emergency, simply turn the engine switch to
the OFF position. Under normal conditions, use the following
procedure.
1. Move the throttle lever to the SLOW position.
Some engine applications use a remotely-mounted throttle control
rather than the engine-mounted throttle lever shown here.
THROTTLE LEVER
SLOW
2. Turn the engine switch to the OFF position.
ENGINE SWITCH
OFF
3. Turn the fuel valve to the CLOSED or OFF position at the source.
18
OPERATION
SETTING ENGINE SPEED
Position the throttle lever for the desired engine speed.
Some engine applications use a remotely-mounted throttle control
rather than the engine-mounted throttle lever shown here.
For engine speed recommendations, refer to the instructions provided
with the equipment powered by this engine.
THROTTLE LEVER
FAST
SLOW
19
SERVICING YOUR ENGINE
THE IMPORTANCE OF MAINTENANCE
Good maintenance is essential for safe, economical, and trouble-free
operation. It will also help reduce air pollution.
Improperly maintaining this engine,
or failure to correct a problem
before operation, can cause a
malfunction in which you can be
seriously hurt or killed.
Always follow the inspection and
maintenance recommendations and
schedules in this owner’s manual.
To help you properly care for your engine, the following pages include
a maintenance schedule, routine inspection procedures, and simple
maintenance procedures using basic hand tools. Other service tasks
that are more difficult, or require special tools, are best handled by
professionals and are normally performed by a Honda technician or
other qualified mechanic.
The maintenance schedule applies to normal operating conditions. If
you operate your engine under unusual conditions, such as sustained
high-load or high-temperature operation, or use in unusually wet or
dusty conditions, consult your servicing dealer for recommendations
applicable to your individual needs and use.
Maintenance, replacement or repair of emission control devices and
systems may be done by any engine repair establishment or
individual, using parts that are ‘‘certified’’ to EPA standards.
20
SERVICING YOUR ENGINE
MAINTENANCE SAFETY
Some of the most important safety precautions follow. However, we
cannot warn you of every conceivable hazard that can arise in
performing maintenance. Only you can decide whether or not you
should perform a given task.
Failure to properly follow
maintenance instructions and
precautions can cause you to be
seriously hurt or killed.
Always follow the procedures and
precautions in the owner’s manual.
Safety Precautions
Make sure the engine is off before you begin any maintenance or
repairs. This will eliminate several potential hazards:
－Carbon monoxide poisoning from engine exhaust.
Be sure there is adequate ventilation whenever you operate the
engine.
－Burns from hot parts.
Let the engine and exhaust system cool before touching.
－Injury from moving parts.
Do not run the engine unless instructed to do so.
Read the instructions before you begin, and make sure you have the
tools and skills required.
To reduce the possibility of fire or explosion, be careful when
working around LPG. Keep cigarettes, sparks and flames away from
all fuel-related parts.
Remember that your servicing dealer knows your engine best and is
fully equipped to maintain and repair it.
To ensure the best quality and reliability, use only new, genuine
Honda parts or their equivalents for repair and replacement.
21
SERVICING YOUR ENGINE
MAINTENANCE SCHEDULE
REGULAR SERVICE PERIOD (3)
ITEM
Each
use
First
month 3 months6 months year
or or or or
20 Hrs. 50 Hrs. 100 Hrs. 200 Hrs.
Every
Every
Every
Refer
to
Perform at every indicated
month or operating hour interval,
whichever comes first.
page
Engine oil
Check level
○
○
○
24
25
(LPG model)
Reduction gear oil
(Equipped model)
Air filter
Change
Check level
Change
Check
○
○
○
－
－
27
○
Clean
○ (1)
28
Replace
Clean
○ (＊)
Sediment cup
Spark plug
○
○
－
Check-adjust
Replace
Clean
30
○
Spark arrester
(optional parts)
Idle speed
○
32
Check-adjust
Check-adjust
Clean
○ (2)
○ (2)
31
Valve clearance
Combustion chamber
－
－
－
－
After every 250 Hrs (2)
Fuel tube (LPG model) Check
Fuel tube Check
○
Every 2 years (Replace if necessary) (2)
Emission-related items.
(＊) Replace the paper element type only.
(1) Service more frequently when used in dusty areas.
(2) These items should be serviced by your servicing dealer, unless
you have the proper tools and are mechanically proficient. Refer
to Honda shop manual for service procedures.
(3) For commercial use, log hours of operation to determine proper
maintenance intervals.
22
SERVICING YOUR ENGINE
FUEL RECOMMENDATIONS
Use LPG with a propane content of 95% or higher.
This engine is certified to operate on LPG only.
Occasionally you may hear a light ‘‘spark knock’’ or ‘‘pinging’’
(metallic rapping noise) while operating under heavy loads. This is no
cause for concern.
If spark knock or pinging occurs at a steady engine speed, under
normal load, change brands of LPG. If spark knock or pinging persists,
see an authorized Honda servicing dealer.
Running the engine with persistent spark knock or pinging can cause
engine damage.
Running the engine with persistent spark knock or pinging is misuse,
and the Distributor’s Limited Warranty does not cover parts damaged
by misuse.
23
SERVICING YOUR ENGINE
ENGINE OIL LEVEL CHECK
Check the engine oil level with the engine stopped and in a level
position.
1. Remove the filler cap/dipstick and wipe it clean.
2. Insert and remove the dipstick without screwing it into the filler neck.
Check the oil level shown on the dipstick.
3. If the oil level is low, fill to the edge of the oil filler hole with the
recommended oil (see page 26).
4. Screw in the filler cap/dipstick securely.
UPPER LIMIT
FILLER CAP/DIPSTICK
LOWER LIMIT
Running the engine with a low oil level can cause engine damage.
The Oil Alert system (applicable engine types) will automatically stop
the engine before the oil level falls below safe limit. However, to avoid
the inconvenience of an unexpected shutdown, always check the
engine oil level before startup.
24
SERVICING YOUR ENGINE
ENGINE OIL CHANGE
Drain the used oil while the engine is warm. Warm oil drains quickly
and completely.
1. Place a suitable container below the engine to catch the used oil,
then remove the filler cap/dipstick and the drain plug.
2. Allow the used oil to drain completely, then reinstall the drain plug,
and tighten it securely.
Please dispose of used motor oil in a manner that is compatible with
the environment. We suggest you take used oil in a sealed container
to your local recycling center or service station for reclamation. Do
not throw it in the trash, pour it on the ground, or down a drain.
3. With the engine in a level position, fill to the outer edge of the oil
filler hole with the recommended oil (see page 26).
Engine oil capacity: 1.16 US qt (1.10 )
Running the engine with a low oil level can cause engine damage.
The Oil Alert system (applicable engine types) will automatically
stop the engine before the oil level falls below the safe limit.
However, to avoid the inconvenience of an unexpected shutdown,
fill to the upper limit, and check the oil level regularly.
4. Screw in the filler cap/dipstick securely.
FILLER CAP/
DIPSTICK
OIL LEVEL
DRAIN PLUG
25
SERVICING YOUR ENGINE
ENGINE OIL RECOMMENDATIONS
Oil is a major factor affecting performance and service life. Use
4-stroke automotive detergent oil that is designed for engines
operating on LPG.
SAE 30 (API service classification SJ) is recommended for general use.
The following are examples of oils that meet Honda’s requirements for
LPG-fueled engines:
Pennzoil HD 30
Valvoline HPO 30
Castrol HD 30
For operation in temperatures below 32°F (0°C), 5W-30 synthetic oil
may be used for easier starting. Do not use 5W-30 synthetic oil when
the air temperature is above 32°F (0°C).
Do not use multigrade mineral-based oils. The use of multigrade
mineral-based oils may result in premature engine wear and/or
damage.
26
SERVICING YOUR ENGINE
AIR FILTER INSPECTION
Remove the air cleaner cover and inspect the filter elements. Clean or
replace dirty filter elements. Always replace damaged filter elements.
Refer to page28 for instructions that apply to the air cleaner and filter
service.
PAPER
FILTER
ELEMENT
FOAM
FILTER
ELEMENT
27
SERVICING YOUR ENGINE
AIR CLEANER SERVICE
A dirty air filter will restrict air flow to the carburetor, reducing engine
performance. If you operate the engine in very dusty areas, clean the
air filter more often than specified in the MAINTENANCE SCHEDULE.
Operating the engine without an air filter, or with a damaged air filter,
will allow dirt to enter the engine, causing rapid engine wear. This type
of damage is not covered by the Distributor’s Limited Warranty.
WING
NUTS
1. Remove the wing nut from the
AIR
CLEANER
COVER
air cleaner cover, and remove
the cover.
2. Remove the wing nut from the
air filter, and remove the filter.
3. Remove the foam filter from the
paper filter.
PAPER
4. Inspect both air filter elements,
and replace them if they are
damaged. Always replace the
paper air filter element at the
scheduled interval (see page
22).
FILTER
ELEMENT
FOAM
FILTER
ELEMENT
GASKET
5. Clean the air filter elements if
they are to be reused.
28
SERVICING YOUR ENGINE
Paper air filter element: Tap the filter element several times on a hard
surface to remove dirt, or blow compressed air [not exceeding 30 psi
(207 kPa, 2.1 kgf/cm )] through the filter element from the inside.
Never try to brush off dirt; brushing will force dirt into the fibers.
Foam air filter element: Clean in warm soapy water, rinse, and allow to
dry thoroughly. Or clean in nonflammable solvent and allow to dry.
Dip the filter element in clean engine oil, then squeeze out all excess
oil. The engine will smoke when started if too much oil is left in the
foam.
6. Wipe dirt from the inside of the air cleaner base and cover, using a
moist rag. Be careful to prevent dirt from entering the air duct that
leads to the carburetor.
7. Place the foam air filter element over the paper element, and
reinstall the assembled air filter. Be sure the gasket is in place
beneath the air filter. Tighten the air filter wing nut securely.
8. Install the air cleaner cover, and tighten the cover wing nut securely.
29
SERVICING YOUR ENGINE
SPARK PLUG SERVICE
Recommended spark plugs: BPR6ES (NGK)
W20EPR-U (DENSO)
An incorrect spark plug can cause engine damage.
1. Disconnect the spark plug cap, and remove any dirt from around the
spark plug area.
2. Remove the spark plug with a 13/16-inch spark plug wrench.
SPARK PLUG WRENCH
3. Inspect the spark plug. Replace it
if the electrodes are worn, or if the
insulator is cracked or chipped.
Clean the spark plug with a wire
brush if you are going to reuse it.
0.028－0.031 in
(0.70－0.80 mm)
4. Measure the spark plug electrode
gap with a suitable gauge. The
gap should be 0.028－0.031 in
(0.70－0.80 mm). Correct the gap,
if necessary, by carefully bending
the side electrode.
5. Install the spark plug carefully, by
hand, to avoid cross-threading.
30
SERVICING YOUR ENGINE
6. After the spark plug seats, tighten with a 13/16-inch spark plug
wrench to compress the washer.
If reinstalling the used spark plug, tighten 1/8－1/4 turn after the
spark plug seats.
If installing a new spark plug, tighten 1/2 turn after the spark plug
seats.
A loose spark plug can overheat and damage the engine.
Overtightening the spark plug can damage the threads in the
cylinder head.
7. Attach the spark plug cap.
IDLE SPEED ADJUSTMENT
1. Start the engine outdoors, and allow it to warm up to operating
temperature.
2. Move the throttle lever to its slowest position.
3. Turn the throttle stop screw to obtain the standard idle speed.
＋200
－150
Standard idle speed: 1,400
rpm
THROTTLE STOP SCREW
31
SERVICING YOUR ENGINE
SPARK ARRESTER SERVICE (optional equipment)
Your engine is not factory-equipped with a spark arrester. In some
areas, it is illegal to operate an engine without a spark arrester. Check
local laws and regulations. A spark arrester is available from
authorized Honda servicing dealers.
The spark arrester must be serviced every 100 hours to keep it
functioning as designed.
If the engine has been running, the muffler will be very hot. Allow the
muffler to cool before servicing the spark arrester.
1. Remove the two 8 mm nuts and remove the muffler from the
cylinder.
2. Remove the three 4 mm screws from the exhaust deflector, and
remove the deflector.
3. Remove the four 5 mm screws from the muffler protector and
remove the muffler protector.
4. Remove the 4 mm screws from the spark arrester, and remove the
spark arrester from the muffler.
5 mm SCREWS
MUFFLER
PROTECTOR
EXHAUST
DEFLECTOR
4 mm SCREW
4 mm
SCREWS
SPARK
ARRESTER
SPARK ARRESTER
MUFFLER
8 mm NUTS
5. Use a brush to remove carbon deposits
from the spark arrester screen. Be
careful to avoid damaging the screen.
The spark arrester must be free of
breaks and holes. Replace the spark
arrester if it is damaged.
SCREEN
6. Install the spark arrester, muffler protector, exhaust deflector, and
muffler in the reverse order of disassembly.
32
HELPFUL TIPS & SUGGESTIONS
STORING YOUR ENGINE
Storage Preparation
Proper storage preparation is essential for keeping your engine
troublefree and looking good. The following steps will help to keep
rust and corrosion from impairing your engine’s function and
appearance, and will make the engine easier to start when you use it
again.
Cleaning
If the engine has been running, allow it to cool for at least half an hour
before cleaning. Clean all exterior surfaces, touch up any damaged
paint, and coat other areas that may rust with a light film of oil.
Using a garden hose or pressure washing equipment can force
water into the air cleaner or muffler opening. Water in the air cleaner
will soak the air filter, and water that passes through the air filter or
muffler can enter the cylinder, causing damage.
Water contacting a hot engine can cause damage. If the engine has
been running, allow it to cool for at least half an hour before
washing.
33
HELPFUL TIPS & SUGGESTIONS
Engine Oil
1. Change the engine oil (see page 25).
Engine Cylinder
1. Remove the spark plug (see page 30).
2. Pour a tablespoon (5－10 cc) of clean engine oil into the cylinder.
3. Pull the starter rope several times to disribute the oil in the cylinder.
4. Reinstall the spark plug.
5. Pull the starter rope slowly until resistance is felt and the notch on
the starter pulley aligns with the hole at the top of the recoil starter
cover. This will close the valves so moisture cannot enter the engine
cylinder. Return the starter rope gently.
Align notch on pulley
with hole at top of cover.
Storage Precautions
Select a well-ventilated storage area away from any appliance that
operates with a flame, such as a furnace, water heater, or clothes dryer.
Also avoid any area with a spark-producing electric motor, or where
power tools are operated.
If possible, avoid storage areas with high humidity, because that
promotes rust and corrosion.
Leave the fuel valve lever in the OFF position at the source to reduce
the possibility of fuel leakage.
34
HELPFUL TIPS & SUGGESTIONS
Position the equipment so the engine is level. Tilting can cause oil
leakage.
With the engine and exhaust system cool, cover the engine to keep out
dust. A hot engine and exhaust system can ignite or melt some
materials. Do not use sheet plastic as a dust cover. A nonporous cover
will trap moisture around the engine, promoting rust and corrosion.
Removal From Storage
Check your engine as described in the BEFORE OPERATION chapter of
this manual.
If the cylinder was coated with oil during storage preparation, the
engine may smoke briefly at startup. This is normal.
35
HELPFUL TIPS & SUGGESTIONS
TRANSPORTING
If the engine has been running, allow it to cool for at least 15 minutes
before loading the engine-powered equipment on the transport
vehicle. A hot engine and exhaust system can burn you and can ignite
some materials.
Keep the engine level when transporting to reduce the possibility of
fuel leakage. Turn the fuel valve OFF at the source.
36
TAKING CARE OF UNEXPECTED PROBLEMS
ENGINE WILL NOT
START
1. Check control
positions.
Possible Cause
Fuel valve OFF.
Choke OPEN.
Engine switch OFF.
Correction
OPEN valve.
Move lever to CLOSED.
Turn engine switch to
ON.
2. Check fuel.
Out of fuel.
Refuel.
3. Remove and inspect
spark plug.
Spark plug faulty,
fouled, or improperly
gapped.
Clean, gap, or replace
spark plug (p. 30).
Spark plug wet with
fuel (flooded engine).
Dry and reinstall spark
plug. Start engine with
throttle lever in FAST
position.
4. Take engine to an
authorized Honda
Carburetor malfunction,
ignition malfunction,
valves stuck, etc.
Replace or repair faulty
components as
necessary.
servicing dealer, or
refer to shop manual.
ENGINE LACKS
POWER
Possible Cause
Correction
1. Check air filter.
Filter element(s)
clogged.
Carburetor malfunction,
ignition malfunction,
valves stuck, etc.
Clean or replace filter
element(s) (p. 28).
Replace or repair faulty
components as
2. Take engine to an
authorized Honda
servicing dealer, or
refer to shop manual.
necessary.
37
TECHNICAL & CONSUMER INFORMATION
TECHNICAL INFORMATION
Serial Number Location
SERIAL NUMBER
& ENGINE TYPE
Record the engine serial number in the space below. You will need this
serial number when ordering parts, and when making technical or
warranty inquires (see page 47 ).
Engine serial number:
38
TECHNICAL & CONSUMER INFORMATION
Remote Control Linkage
The throttle and choke control levers are provided with holes for
optional cable attachment. The following illustrations show
installation examples for a solid wire cable and for a flexible, braided
wire cable. If using a flexible, braided wire cable, add a return spring
as shown.
It is necessary to loosen the throttle lever friction nut when operating
the throttle with a remotely-mounted control.
REMOTE THROTTLE LINKAGE
RETURN SPRING
THROTTLE LEVER
FRICTION NUT
Flexible wire core
mounting
4 mm SCREW
WIRE HOLDER
OPTIONAL
WIRE
THROTTLE
LEVER
5 mm
CIRCLIP
Solid wire core
mounting
REMOTE CHOKE LINKAGE
WIRE HOLDER
CHOKE LEVER
39
TECHNICAL & CONSUMER INFORMATION
Carburetor Modification for High Altitude Operation
The GX270 and GX390 LPG-fueled engine do not require any
modifications for high-altitude operation. However, performance will
decrease at high altitudes.
Fuel Regulator Information
This engine is certified to comply with U.S. EPA and California ARB
emission regulations using the Impco Beam regulator specified in the
installation instructions (see below).
Honda used this regulator and other specific parts and adjustments to
demonstrate compliance with the emission regulations. Adjustable
fuel system parts must have U.S. EPA and California ARB approved
tamper resistant features to limit the available adjustment after the
fuel system is correctly installed.
If an equipment manufacturer did not install your engine in a product,
you will need the installation instructions for the Honda certified
system (see below).
If you choose not to use the Honda fuel system, you must use a
system that has been certified by the fuel system manufacturer to be
used on this Honda engine.
Or, if you use a fuel system that is not already certified, you must have
certification test data satisfactory to the U.S. EPA or California ARB.
The test data must prove the system will meet the emission standard
both when the engine is new and at the end of its emission durability
period (hours).
To obtain a copy of the installation instructions for this engine, contact
an independent Honda engine distributor, or our Customer Service
Department (page 47 ).
40
TECHNICAL & CONSUMER INFORMATION
Emission Control System Information
Source of Emissions
The combustion process produces carbon monoxide, oxides of
nitrogen, and hydrocarbons. Control of hydrocarbons and oxides of
nitrogen is very important because, under certain conditions, they
react to form photochemical smog when subjected to sunlight. Carbon
monoxide does not react in the same way, but it is toxic.
Honda utilizes lean carburetor settings and other systems to reduce
the emissions of carbon monoxide, oxides of nitrogen and
hydrocarbons.
The U.S. and California Clean Air Acts
EPA and California regulations require all manufacturers to furnish
written instructions describing the operation and maintenance of
emission control systems.
The following instructions and procedures must be followed in order
to keep the emissions from your Honda engine within the emission
standards.
Tampering and Altering
Tampering with or altering the emission control system may increase
emissions beyond the legal limit. Among those acts that constitute
tampering are:
Removal or alteration of any part of the intake, fuel or exhaust
systems.
Altering or defeating the governor linkage or speed-adjusting
mechanism to cause the engine to operate outside its design
parameters.
41
TECHNICAL & CONSUMER INFORMATION
Problems That May Affect Emissions
If you are aware of any of the following symptoms, have your engine
inspected and repaired by your servicing dealer.
Hard starting or stalling after starting.
Rough idle.
Misfiring or backfiring under load.
Afterburning (backfiring).
Black exhaust smoke or high fuel consumption.
Replacement Parts
The emission control systems on your Honda engine were designed,
built, and certified to conform with EPA and California emission
regulations. We recommend the use of genuine Honda parts
whenever you have maintenance done. These original-design
replacement parts are manufactured to the same standards as the
original parts, so you can be confident of their performance. The use
of replacement parts that are not of the original design and quality
may impair the effectiveness of your emission control system.
A manufacturer of an aftermarket part assumes the responsibility that
the part will not adversely affect emission performance. The
manufacturer or rebuilder of the part must certify that use of the part
will not result in a failure of the engine to comply with emission
regulations.
Maintenance
Follow the maintenance schedule on page 22. Remember that this
schedule is based on the assumption that your machine will be used
for its designed purpose. Sustained high-load or high-temperature
operation, or use in unusually wet or dusty conditions, will require
more frequent service.
42
TECHNICAL & CONSUMER INFORMATION
Air Index
An Air Index Information hang tag/label is applied to engines certified
to an emission durability time period in accordance with the
requirements of the California Air Resources Board.
The bar graph is intended to provide you, our customer, the ability to
compare the emissions performance of available engines. The lower
the Air Index, the less pollution.
The durability description is intended to provide you with information
relating to the engine’s emission durability period. The descriptive
term indicates the useful-life period for the engine’s emission control
system. See your Emission Control Warranty for additional
information.
Descriptive Term
Moderate
Applicable to Emissions Durability Period
50 hours (0－65 cc)
125 hours (greater than 65 cc)
Intermediate
Extended
125 hours (0－65 cc)
250 hours (greater than 65 cc)
300 hours (0－65 cc)
500 hours (greater than 65 cc)
The Air Index Information hang tag must remain on the engine until it
is sold. Remove the hang tag before operating the engine.
43
TECHNICAL & CONSUMER INFORMATION
Specifications
GX270
15.7 × 16.9 × 16.0 in
(400 × 430 × 407 mm)
Length × Width × Height
50.7 lbs (23.0 kg)
Dry weight
4-stroke, overhead valve, single cylinder
16.5 cu-in (270 cm )
Engine type
Displacement
[Bore × Stroke]
Max. output
[ 3.0 × 2.3 in (77 × 58 mm) ]
8.9 bhp (6.6 kW, 9.0 PS) at 3,600 rpm
14.1 lbf·ft (19.1 N·m, 1.95 kgf·m) at 2,500 rpm
0.42 lb/hph (258 g/kWh, 190 g/PSh)
Forced air
Max. torque
Fuel consumption
Cooling system
Ignition system
PTO shaft rotation
Transistorized magneto
Counterclockwise
GX390
16.7 × 17.7 × 17.4 in
(425 × 450 × 443 mm)
Length × Width × Height
63.9 lbs (29.0 kg)
Dry weight
4-stroke, overhead valve, single cylinder
23.7 cu-in (389 cm )
Engine type
Displacement
[Bore × Stroke]
Max. output
[ 3.5 × 2.5 in (88 × 64 mm) ]
12.9 bhp (9.6 kW, 13.0 PS) at 3,600 rpm
19.5 lbf·ft (26.5 N·m, 2.7 kgf·m) at 2,500 rpm
0.42 lb/hph (258 g/kWh, 190 g/PSh)
Forced air
Max. torque
Fuel consumption
Cooling system
Ignition system
PTO shaft rotation
Transistorized magneto
Counterclockwise
GX270/GX390 Tuneup
ITEM
Spark plug gap
SPECIFICATION
0.028－0.031 in
MAINTENANCE
Refer to page: 30
(0.70－0.80 mm)
IN: 0.15 ± 0.02 mm(cold)
EX: 0.20 ± 0.02 mm(cold)
Valve clearance
See your authorized
Honda dealer
No other adjustments needed.
Other specifications
44
TECHNICAL & CONSUMER INFORMATION
Wiring Diagram
Engine Types With Oil Alert
45
TECHNICAL & CONSUMER INFORMATION
CONSUMER INFORMATION
Honda Publications
These publications will give you additional information for
maintaining and repairing your engine. You may order them from
your Honda engine dealer.
Shop Manual
This manual covers complete maintenance and overhaul procedures.
It is intended to be used by a skilled technician.
Parts Catalog
This manual provides complete, illustrated parts lists.
46
TECHNICAL & CONSUMER INFORMATION
Warranty Service Information
Servicing dealership personnel are trained professionals. They should
be able to answer any question you may have. If you encounter a
problem that your dealer does not solve to your satisfaction, please
discuss it with the dealership’s management. The Service Manager or
General Manager can help. Almost all problems are solved in this way.
If you are dissatisfied with the decision made by the dealership’s
management, contact the Honda Power Equipment Customer
Relations Office. You can write to:
American Honda Motor Co., Inc.
Power Equipment Division
Customer Relations Office
4900 Marconi Drive
Alpharetta, Georgia 30005-8847
Or telephone: (770) 497-6400
When you write or call, please give us this information:
Model and serial number (see page 38 )
Name of dealer who sold the engine to you
Name and address of dealer who services your engine
Date of purchase
Your name, address and telephone number
A detailed description of the problem
47
MEMO
48
QUICK REFERENCE INFORMATION
Fuel
Type
Type
LPG with a propane content of
95 % or higher (page 23)
SAE 30, API SJ, for general use
(page 26)
Engine Oil
Capacity
Type
1.16 US qt (1.10 )
Spark Plug
NGK: BPR6ES ,
DENSO: W20EPR-U
Gap
0.028－0.031 in (0.70－0.80 mm)
(page 30)
＋200
Carburetor
Maintenance
Idle speed
Before
each use
First 20
hours
Subsequent
1,400
rpm (page 31)
－150
Check engine oil level.
Check air filter.
Change engine oil.
Refer to the maintenance
schedule on page 22.
K1:GX390
300.2003.10
A H
英
N
H C
31ZK6601
00X31-ZK6-6010
EM3
Printed in Japan
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