Owner’s Manual
GX22•GX31
o2003 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. 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.
These engines are emissions-certified for use in handheld equipment.
They can only be used to power products that are defined by the
California Air Resources Board and the U.S. EPA as handheld.
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 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
Choke Lever ........................................................................................ 8
Throttle Lever ..................................................................................... 9
Recoil Starter Grip ............................................................................ 10
FEATURES ............................................................................................ 11
Centrifugal Clutch ............................................................................ 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
Hot Restart ........................................................................................ 16
STOPPING THE ENGINE ..................................................................... 17
SETTING ENGINE SPEED .................................................................... 18
SERVICING YOUR HONDA ENGINE ...................................................... 19
THE IMPORTANCE OF MAINTENANCE ............................................. 19
MAINTENANCE SAFETY ..................................................................... 20
MAINTENANCE SCHEDULE ............................................................... 21
REFUELING ........................................................................................... 22
FUEL RECOMMENDATIONS .............................................................. 23
ENGINE OIL LEVEL CHECK ................................................................. 24
ENGINE OIL CHANGE .......................................................................... 26
ENGINE OIL RECOMMENDATIONS ................................................... 28
AIR FILTER INSPECTION ..................................................................... 29
AIR FILTER CLEANING ........................................................................ 30
SPARK PLUG SERVICE ........................................................................ 31
COOLING FIN INSPECTION ................................................................ 33
FUEL FILTER INSPECTION and FUEL TANK CLEANING .................. 34
SPARK ARRESTER SERVICE ............................................................... 36
3
CONTENTS
HELPFUL TIPS & SUGGESTIONS ...........................................................40
STORING YOUR ENGINE .................................................................... 40
Storage Preparation ......................................................................... 40
Storage Precautions ......................................................................... 43
Removal From Storage .................................................................... 43
TRANSPORTING .................................................................................. 44
TAKING CARE OF UNEXPECTED PROBLEMS ...................................... 45
ENGINE WILL NOT START .................................................................. 45
ENGINE LACKS POWER ...................................................................... 45
TECHNICAL & CONSUMER INFORMATION ......................................... 46
TECHNICAL INFORMATION ................................................................ 46
Serial Number Location ................................................................... 46
Remote Control Linkage .................................................................. 47
Carburetor Modification for High Altitude Operation ................... 48
Oxygenated Fuels ............................................................................ 49
Emission Control System Information ........................................... 50
Air Index ............................................................................................ 52
Specifications ................................................................................... 53
Wiring Diagram ................................................................................ 54
CONSUMER INFORMATION ............................................................... 55
Honda Publications .......................................................................... 55
Warranty Service Information ......................................................... 56
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
Gasoline is extremely flammable, and gasoline vapor can explode.
Refuel outdoors, in a well-ventilated area, with the engine stopped.
Never smoke near gasoline, and keep other flames and sparks away.
Always store gasoline in an approved container. If any fuel is spilled,
make sure the area is dry before starting the engine.
5
ENGINE SAFETY
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.
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, operation, or protective
apparel that may be needed to operate the equipment.
6
CONTROLS & FEATURES
COMPONENT & CONTROL LOCATIONS
Horizontal type:
SPARK PLUG
CHOKE LEVER
AIR CLEANER
MUFFLER
(inside the cover)
STARTER GRIP
PRIMING BULB
FUEL FILLER CAP
FUEL TANK
RECOIL STARTER
OIL FILLER CAP
RECOIL STARTER
STARTER GRIP
FUEL FILLER CAP
Vertical type:
SPARK ARRESTER
MUFFLER
(inside the cover)
SPARK PLUG
OIL FILLER CAP
FUEL TANK
PRIMING BULB
AIR CLEANER
CHOKE LEVER
7
CONTROLS & FEATURES
CONTROLS
Choke Lever
The choke lever opens and closes the choke valve in the carburetor.
The CLOSED position enriches the fuel mixture for starting a cold
engine.
The OPEN position provides the correct fuel mixture for operation
after starting, and for restarting a warm engine.
CHOKE LEVER
CLOSED
OPEN
8
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.
The throttle lever shown here will be connected to a remote control on
the equipment powered by this engine. Refer to the instructions
provided with that equipment for remote control information.
THROTTLE LEVER
SLOW
FAST
9
CONTROLS & FEATURES
Recoil Starter Grip
Pulling the starter grip operates the recoil starter to crank the engine.
Horizontal type:
STARTER GRIP
(EQUIPMENT SIDE)
Vertical type:
(EQUIPMENT SIDE)
STARTER GRIP
10
CONTROLS & FEATURES
FEATURES
Centrifugal Clutch
The centrifugal clutch automatically engages and transmits power
when engine speed is increased above approximately 4,000 rpm. At
idle speed, the clutch is disengaged.
Do not run the engine without mounting it on equipment that includes
the centrifugal clutch drum and housing, or centrifugal force will cause
the clutch shoes to contact and damage the engine case.
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 ignition switch on the equipment is in the OFF position.
Check the General Condition of the Engine
Look around and underneath the engine for signs of oil or gasoline
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.
Check the air filter (see page29 ). A dirty air filter will restrict air flow
to the carburetor, reducing engine performance.
Check that all nuts, bolts, and screws are tightened.
Check the fuel level. Starting with a full tank will help to eliminate or
reduce operating interruptions for refueling.
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. To start a cold engine, move the choke lever to the CLOSED position.
To restart a warm engine, leave the choke lever in the OPEN position.
CHOKE LEVER
CLOSED
OPEN
14
OPERATION
2. Press the priming bulb repeatedly until fuel can be seen in the clear-
plastic fuel-return tube.
FUEL RETURN TUBE
(clear plastic tube)
PRIMING BULB
3. Turn the ignition switch to the ON position.
4. Pull the starter grip lightly until you feel resistance, then pull briskly.
Return the starter grip gently.
Horizontal type:
Vertical type:
(EQUIPMENT SIDE)
STARTER GRIP
STARTER GRIP
(EQUIPMENT SIDE)
15
OPERATION
5. If the choke lever was moved to the CLOSED position to start the
engine, gradually move it to the OPEN position as the engine warms
up.
CHOKE LEVER
OPEN
Hot Restart
If the engine is operated at higher ambient temperatures then turned
off and allowed to sit for a short time, if may not restart on the first pull.
If necessary, use the following procedure:
The ignition switch and the throttle lever are located on the equipment
not on the engine.
IMPORTANT SAFETY PRECAUTION
Turn the ignition switch to the OFF position before performing the
following procedure. This will prevent the engine from starting and
running at maximum speed when the throttle is in the full throttle
position. If the engine starts, with the throttle in the full throttle
position, the equipment can move forward rapidly or the trimmer
attachment can spin at maximum speed. This may result in personal
injury.
1. Turn the ignition switch to the OFF position.
2. Move the choke lever to the OPEN position.
3. Hold the throttle lever in the full throttle position.
4. Pull the starter grip 3 to 5 times.
5. Follow the STARTING THE ENGINE procedure on page 14 and start
the engine with the choke lever in the OPEN position.
16
OPERATION
STOPPING THE ENGINE
To stop the engine in an emergency, simply turn the ignition switch on
the equipment to the OFF position. Under normal conditions, use the
following procedure.
1. Move the throttle lever to the SLOW position.
The throttle lever shown here will be connected to a remote control
on the equipment powered by this engine. Refer to the instructions
provided with that equipment for remote control information.
THROTTLE LEVER
SLOW
2. Turn the ignition switch on the equipment to the OFF position.
17
OPERATION
SETTING ENGINE SPEED
Position the throttle lever for the desired engine speed.
The throttle lever shown here will be connected to a remote control on
the equipment powered by this engine. Refer to the instructions
provided with that equipment for remote control information and for
engine speed recommendations.
For engine speed recommendations, refer to the instructions provided
with the equipment powered by this engine.
Be careful not to increase engine speed above 8,500 rpm for the
vertical type engine.
Be careful not to increase engine speed above 10,000 rpm for the
horizontal type engine.
THROTTLE LEVER
SLOW
FAST
18
SERVICING YOUR HONDA 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.
19
SERVICING YOUR HONDA 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 gasoline. Use only a nonflammable solvent, not
gasoline, to clean parts. 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.
20
SERVICING YOUR HONDA ENGINE
MAINTENANCE SCHEDULE
REGULAR SERVICE PERIOD (3)
First
month
or
Every
3 months
or
Every
year
or
Every
6 months
or
Every
2 years
or
ITEM
Refer
to
page
Each
use
Perform at every indicated
month or operating hour
interval, whichever comes first.
10 hrs.
25 hrs.
100 hrs.
50 hrs.
300 hrs.
Engine oil
Check level
Change
Check
Clean
Check
○
○
○
24
26
29
30
－
○
○
Air filter
○ (1)
Nuts, bolts, fasteners
(Retighten if necessary)
Spark plug
Check-adjust
Replace
○
31
○
Engine cooling fins Check
○
33
36
34
Spark arrester
Fuel tank
Clean
Clean
○
○
○
Fuel filter
Check
34
Clutch shoes
Idle speed
Valve clearance
Combustion
chamber
Check
○ (2)
－
－
－
－
Check-adjust
Check-adjust
Clean
○ (2)
○ (2)
After every 300 hrs (2)
Fuel tubes
Check
Every 2 years (Replace if necessary) (2)
－
Emission-related items.
(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.
21
SERVICING YOUR HONDA ENGINE
REFUELING
Fuel tank capacities
GX22:0.119 US gal (0.45 , 0.099 Imp gal) for horizontal types
0.159 US gal (0.60 , 0.132 Imp gal) for vertical types
GX31:0.172 US gal (0.65 , 0.143 Imp gal) for horizontal types
0.159 US gal (0.60 , 0.132 Imp gal) for vertical types
Check the fuel level by looking through the translucent fuel tank.
If the fuel level is low, refuel in a well-ventilated area with the engine
stopped. If the engine has been running, allow it to cool.
To refuel, rest the engine on the ground with the fuel tank cap facing
up, as shown. Remove the fuel tank cap, and fill the tank with gasoline
to the bottom of the filler neck. Refuel carefully to avoid spilling fuel.
Do not overfill. There should be no fuel in the filler neck. After
refueling, tighten the fuel tank cap securely.
Gasoline is highly flammable and
explosive.
You can be burned or seriously
injured when handling fuel.
Stop the engine and keep heat,
sparks, and flame away.
Handle fuel only outdoors.
Wipe up spills immediately.
Horizontal type:
Vertical type:
FUEL TANK CAP
MAXIMUM FUEL LEVEL
22
SERVICING YOUR HONDA ENGINE
Never refuel the engine inside a building where gasoline fumes may
reach flames or sparks. Keep gasoline away from appliance pilot lights,
barbecues, electric appliances, power tools, etc.
Spilled fuel is not only a fire hazard, it causes environmental damage.
Wipe up spills immediately.
Fuel can damage paint and plastic. Be careful not to spill fuel when
filling your fuel tank. Damage caused by spilled fuel is not covered
under warranty.
FUEL RECOMMENDATIONS
Use unleaded gasoline with a pump octane rating of 86 or higher.
These engines are certified to operate on unleaded gasoline. Unleaded
gasoline produces fewer engine and spark plug deposits and extends
exhaust system life.
Never use stale or contaminated gasoline or an oil/gasoline mixture.
Avoid getting dirt or water in the fuel tank.
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 gasoline. 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 HONDA ENGINE
ENGINE OIL LEVEL CHECK
Check the engine oil level before each use, or every 10 hours if
operated continuously.
Check the engine oil level with the engine stopped and in a level
position.
For the vertical type engine, turn it 90 degrees with the fuel tank
downward before performing engine oil level check.
1. Remove the oil 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 28). To avoid overfilling or underfilling,
be sure the engine is in a level position, as shown, while adding oil.
Horizontal type:
Vertical type:
OIL FILLER CAP/DIPSTICK
UPPER LIMIT
FUEL TANK
24
SERVICING YOUR HONDA ENGINE
4. Reinstall the oil filler cap/dipstick securely.
Running the engine with a low or excessive oil level can cause engine
damage.
25
SERVICING YOUR HONDA ENGINE
ENGINE OIL CHANGE
Drain the used oil while the engine is warm. Warm oil drains quickly
and completely.
For the vertical type engine, turn it 90 degrees with the fuel tank
downward before performing engine oil change.
1. Check that the fuel tank cap is tightened securely.
2. Place a suitable container next to the engine to catch the used oil.
3. Remove the oil filler cap/dipstick and drain the oil into the container
by tipping the engine toward the oil filler neck.
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.
OIL FILLER NECK
FUEL TANK CAP
26
SERVICING YOUR HONDA ENGINE
4. With the engine in a level position, fill to the edge of the oil filler hole
with the recommended oil (see page 28).
Add the engine oil slowly to avoid overflowing, as the engine oil
tank capacity is small.
Engine oil capacity: 0.11 US qt (0.10 , 0.09 Imp qt)
Running the engine with a low or excessive oil level can cause
engine damage.
5. Reinstall the oil filler cap/dipstick securely.
Horizontal type:
Vertical type:
OIL FILLER CAP/DIPSTICK
UPPER LIMIT
27
SERVICING YOUR HONDA ENGINE
ENGINE OIL RECOMMENDATIONS
Oil is a major factor affecting performance and service life. Use
4-stroke automotive detergent oil.
SAE 10W-30 is recommended for general use. Other viscosities shown
in the chart may be used when the average temperature in your area is
within the recommended range.
SAE Viscosity Grades
AMBIENT TEMPERATURE
The SAE oil viscosity and service classification are in the API label on
the oil container. Honda recommends that you use API SERVICE
category SJ oil.
The recommended operating range of this engine is 23°F to 104°F
(－5°C to 40°C).
28
SERVICING YOUR HONDA ENGINE
AIR FILTER INSPECTION
Press the latch tab on the top of the air cleaner cover, and remove the
cover. Check the filter to be sure it is clean and in good condition.
If the filter is dirty, clean it as described on page 30. Replace the filter if
it is damaged.
Reinstall the filter and air cleaner cover.
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.
Vertical type:
FILTER
UPPER
TAB
AIR CLEANER
COVER
Horizontal type:
FILTER
CHOKE LEVER
AIR CLEANER BODY
AIR CLEANER COVER
UPPER TAB
AIR CLEANER BODY
LOWER TABS
29
SERVICING YOUR HONDA ENGINE
AIR FILTER CLEANING
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 than specified in the MAINTENANCE SCHEDULE.
1. Clean the air filter in warm soapy water, rinse, and allow to dry
thoroughly. Or clean in nonflammable solvent and allow to dry.
2. Dip the air filter 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.
3. Wipe dirt from the air cleaner body and cover, using a moist rag. Be
careful to prevent dirt from entering the carburetor.
Vertical type:
FILTER
Horizontal type:
FILTER
30
SERVICING YOUR HONDA ENGINE
SPARK PLUG SERVICE
Recommended spark plug: CR5HSB(NGK)
U16FSR-UB (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 5/8-inch spark plug wrench.
SPARK PLUG
SPARK PLUG CAP
3. Inspect the spark plug. Replace it if
the electrodes are worn, or if the
insulator is cracked or chipped.
0.024－0.028 in
(0.60－0.70 mm)
Clean the spark plug with a wire
brush if you are going to reuse it.
4. Measure the spark plug electrode
gap with a suitable gauge. The gap
should be 0.024－0.028 in (0.60－
0.70 mm). Correct the gap, if
necessary, by carefully bending the
side electrode.
5. Install the spark plug carefully, by
hand, to avoid cross-threading.
31
SERVICING YOUR HONDA ENGINE
6. After the spark plug seats, tighten with a 5/8-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.
32
SERVICING YOUR HONDA ENGINE
COOLING FIN INSPECTION
Inspect the engine cooling fins, and clean out debris if they are
clogged.
If it is necessary to remove the top cover for better access to the
cooling fins, refer to the disassembly instructions on pages 37 and 38 .
COOLING FINS
(inside the cover)
33
SERVICING YOUR HONDA ENGINE
FUEL FILTER INSPECTION and FUEL TANK CLEANING
1. Check that the engine oil filler cap is tightened securely.
2. Remove the fuel tank cap, and drain the fuel into an approved
gasoline container by tipping the engine toward the fuel filler neck.
Gasoline is highly flammable and
explosive.
You can be burned or seriously
injured when handling fuel.
Keep heat, sparks and flame away.
Handle fuel only outdoors.
Wipe up spills immediately.
FUEL FILLER NECK
ENGINE OIL FILLER CAP
34
SERVICING YOUR HONDA ENGINE
3. Pull the fuel filter out through the fuel filler neck by hooking the
black fuel tube with a piece of wire, such as a partly straightened
paper clip.
4. Inspect the fuel filter. If the fuel filter is dirty, wash it gently with
nonflammable or high flashpoint solvent. If the fuel filter is
excessively dirty, replace it.
Horizontal type:
Vertical type:
FUEL FILTER
5. Rinse sediment from the fuel tank, using nonflammable or high
flashpoint solvent.
6. Insert the fuel filler into the fuel tank and tighten the fuel filter cap
securely.
35
SERVICING YOUR HONDA ENGINE
SPARK ARRESTER SERVICE
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.
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.
SPARK ARRESTER SCREEN
To reach the spark arrester screen on vertical-shaft engines, remove
the deflector guard from the engine top cover and the deflector from
the spark arrester by removing the 4 mm screws as shown below for
reaching the spark arrester screen.
DEFLECTOR GUARD
TOP COVER
4 mm SCREWS
DEFLECTOR
SPARK ARRESTER
36
SERVICING YOUR HONDA ENGINE
Remove and clean the spark arrester in the following manner, or have
it serviced by your Honda dealer, if it becomes fouled excessively.
1. Remove the air cleaner cover (see page 29).
2. Remove the spark plug cap, and then remove the spark plug wire
and the ignition switch wire from their retainers on the engine top
cover.
RETAINERS
IGNITION SWITCH WIRE
SPARK PLUG WIRE
3. Remove the four 5 mm bolts from the recoil starter, and remove the
recoil starter.
RECOIL STARTER
5 × 18 mm BOLTS
37
SERVICING YOUR HONDA ENGINE
4. Remove the two 5 mm bolts from the top cover, and remove the top
cover.
TOP COVER
5 × 22 mm BOLTS
5. Remove the three 5 mm screws from the muffler cover, and remove
the muffler cover.
6. Remove the 4 mm screw from the spark arrester, and remove the
spark arrester from the muffler.
MUFFLER
5 × 16 mm SCREW
MUFFLER COVER
SPARK ARRESTER
5 × 10 mm SCREW
4 mm SCREW
5 × 8 mm SCREW
38
SERVICING YOUR HONDA ENGINE
7. 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.
SPARK ARRESTER SCREEN
8. Install the spark arrester, muffler cover, top cover, and recoil starter
in the reverse order of disassembly.
9. Secure the ignition switch wire and spark plug wire in the retainers
on the engine top cover.
RETAINERS
SPARK PLUG WIRE
IGNITION SWITCH WIRE
39
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 to start easier 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.
Fuel
Gasoline will oxidize and deteriorate in storage. Old gasoline will
cause hard starting, and it leaves gum deposits that clog the fuel
system. If the gasoline in your engine deteriorates during storage, you
may need to have the carburetor and other fuel system components
serviced or replaced.
The length of time that gasoline can be left in your fuel tank and
carburetor without causing functional problems will vary with such
factors as gasoline blend, your storage temperatures, and whether the
fuel tank is partially or completely filled. The air in a partially filled fuel
tank promotes fuel deterioration. Very warm storage/temperatures
accelerate fuel deterioration. Fuel deterioration problems may occur
within a few months, or even less if the gasoline was not fresh when
you filled the fuel tank.
40
HELPFUL TIPS & SUGGESTIONS
The Distributor’s Limited Warranty does not cover fuel system
damage or engine performance problems resulting from neglected
storage preparation.
You can extend fuel storage life by adding a fuel stabilizer that is
formulated for that purpose, or you can avoid fuel deterioration
problems by draining the fuel tank and carburetor.
ADDING A FUEL STABILIZER TO EXTEND FUEL STORAGE LIFE
When adding a fuel stabilizer, fill the fuel tank with fresh gasoline. If
only partially filled, air in the tank will promote fuel deterioration
during storage. If you keep a container of gasoline for refueling, be
sure that it contains only fresh gasoline.
1. Add fuel stabilizer following the manufacture’s instructions.
2. After adding a fuel stabilizer, run the engine outdoors for 10 minutes
to be sure that treated gasoline has replaced the untreated gasoline
in the carburetor.
41
HELPFUL TIPS & SUGGESTIONS
DRAINING THE FUEL TANK AND CARBURETOR
1. Remove the fuel tank cap and drain the fuel into an approved
gasoline container by tipping the engine toward the fuel filler neck.
2. Press the priming bulb several times until there is no more fuel in
the fuel return tube.
3. Tip the engine toward the fuel filler neck again to drain the fuel.
Gasoline is highly flammable and
explosive.
You can be burned or seriously
injured when handling fuel.
Keep heat, sparks and flame away.
Handle fuel only outdoors.
Wipe up spills immediately.
PRIMING BULB
FUEL RETURN TUBE
FUEL FILLER NECK
ENGINE OIL FILLER CAP
4. After all fuel has drained, reinstall the fuel tank cap securely.
42
HELPFUL TIPS & SUGGESTIONS
Engine Oil
1. Change the engine oil (see page 26).
2. Remove the spark plug (see page 31).
3. Pour a teaspoon (1－3 cc) of clean engine oil into the cylinder.
4. Pull the starter rope several times to distribute the oil in the cylinder.
5. Reinstall the spark plug.
Storage Precautions
If your engine will be stored with gasoline in the fuel tank and
carburetor, it is important to reduce the hazard of gasoline vapor
ignition. 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.
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 fuel was drained during storage preparation, fill the tank with
fresh gasoline. If you keep a container of gasoline for refueling, be
sure that it contains only fresh gasoline. Gasoline oxidizes and
deteriorates over time, causing hard starting.
If the cylinder was coated with oil during storage preparation, the
engine may smoke briefly at startup. This is normal.
43
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.
44
TAKING CARE OF UNEXPECTED PROBLEMS
ENGINE WILL NOT
START
1. Check control
positions.
Possible Cause
Choke open.
Correction
Move the choke lever
to CLOSED position
unless engine is warm.
Turn ignition switch to
ON.
Ignition switch OFF.
(on the equipment)
Out of fuel.
2. Check fuel.
Refuel.
Bad fuel; engine stored
without treating or
draining gasoline, or
refueled with bad
gasoline.
Drain fuel tank and
carburetor (p. 42).
Refuel with fresh
gasoline.
3. Remove and inspect
spark plug.
Spark plug faulty,
fouled, or improperly
gapped.
Clean, gap, or replace
spark plug (p. 31).
Spark plug wet with
fuel (flooded engine).
Dry and reinstall spark
plug. Start engine with
throttle lever in FAST
position, with choke
lever in OPEN position.
Replace or repair faulty
components as
4. Take engine to an
authorized Honda
Fuel filter clogged,
carburetor malfunction,
ignition malfunction,
valves stuck, etc.
servicing dealer, or
refer to shop manual.
necessary.
ENGINE LACKS
POWER
Possible Cause
Correction
1. Check air filter.
Filter element clogged.
Clean or replace filter
element (p. 30).
Drain fuel tank and
carburetor (p. 42).
Refuel with fresh
gasoline.
2. Check fuel.
Bad fuel; engine stored
without treating or
draining gasoline, or
refueled with bad
gasoline.
3. Take engine to an
authorized Honda
Fuel filter clogged,
carburetor malfunction,
ignition malfunction,
valves stuck, etc.
Replace or repair faulty
components as
necessary.
servicing dealer, or
refer to shop manual.
45
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 56).
Engine serial number:
46
TECHNICAL & CONSUMER INFORMATION
Remote Control Linkage
The throttle control lever is provided with a fitting for cable attachment.
Remove the air cleaner cover (see page 29 ) for access to the throttle
lever and cable fitting.
CABLE ATTACHMENT FITTING
THROTTLE CABLE
47
TECHNICAL & CONSUMER INFORMATION
Carburetor Modification for High Altitude Operation
At high altitude, the standard carburetor air-fuel mixture will be too
rich. Performance will decrease, and fuel consumption will increase. A
very rich mixture will also foul the spark plug and cause hard starting.
Operation at an altitude that differs from that at which this engine was
certified, for extended periods of time, may increase emissions.
High altitude performance can be improved by specific modifications
to the carburetor. If you always operate your engine at altitudes above
5,000 feet (1,500 meters), have your servicing dealer perform this
carburetor modification. This engine, when operated at high altitude
with the carburetor modifications for high altitude use, will meet each
emission standard throughout its useful life.
Even with carburetor modification, engine horsepower will decrease
about 3.5% for each 1,000-foot (300-meter) increase in altitude. The
effect of altitude on horsepower will be greater than this if no
carburetor modification is made.
When the carburetor has been modified for high altitude operation,
the air-fuel mixture will be too lean for low altitude use. Operation at
altitudes below 5,000 feet (1,500 meters) with a modified carburetor
may cause the engine to overheat and result in serious engine damage.
For use at low altitudes, have your servicing dealer return the
carburetor to original factory specifications.
48
TECHNICAL & CONSUMER INFORMATION
Oxygenated Fuels
Some conventional gasolines are being blended with alcohol or an
ether compound. These gasolines are collectively referred to as
oxygenated fuels.
To meet clean air standards, some areas of the United States and
Canada use oxygenated fuels to help reduce emissions.
If you use an oxygenated fuel, be sure it is unleaded and meets the
minimum octane rating requirement.
Before using an oxygenated fuel, try to confirm the fuel’s contents.
Some states/provinces require this information to be posted on the
pump.
The following are the EPA approved percentages of oxygenates:
ETHANOL ––––––––(ethyl or grain alcohol) 10% by volume
You may use gasoline containing up to 10%
ethanol by volume. Gasoline containing ethanol
may be marketed under the name ‘‘Gasohol’’.
MTBE ––––––––––––(methyl tertiary butyl ether) 15% by volume
You may use gasoline containing up to 15% MTBE
by volume.
METHANOL ––––––(methyl or wood alcohol) 5% by volume
You may use gasoline containing up to 5%
methanol by volume, as long as it also contains
cosolvents and corrosion inhibitors to protect the
fuel system. Gasoline containing more than 5%
methanol by volume may cause starting and/or
performance problems. It may also damage metal,
rubber, and plastic parts of your fuel system.
If you notice any undesirable operating symptoms, try another service
station, or switch to another brand of gasoline.
Fuel system damage or performance problems resulting from the use
of an oxygenated fuel containing more than the percentages of
oxygenates mentioned above are not covered under warranty.
49
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.
50
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 21. 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.
51
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.
52
TECHNICAL & CONSUMER INFORMATION
Specifications
GX22
Type
Horizontal (SA2)
Vertical (TA2)
8.3 × 9.9 × 9.8 in
(210 × 251 × 249 mm)
8.3 × 9.1 × 9.8 in
(210 × 230 × 249 mm)
Length × Width × Height
7.3 lbs (3.3 kg)
Dry weight
4-stroke, overhead valve, single cylinder
1.3 cu-in (22 cm )
Engine type
Displacement
[1.3 × 1.0 in (33 × 26 mm)]
1.0 bhp (0.74 kW, 1.0 PS) at 7,000 rpm
0.80 lbf·ft (1.09 N·m, 0.11 kgf·m) at 4,500 rpm
[Bore × Stroke]
Max. output
Max. torque
10,000 rpm
8,500 rpm
Max. rotation with no load
Fuel consumption
Cooling system
Ignition system
PTO shaft rotation
0.55 lb/hph (340 g/kWh, 250 g/PSh)
Forced air
Transistorized magneto
Counterclockwise
GX31
Type
Horizontal (SA2)
Vertical (TA2)
8.3 × 9.9 × 9.8 in
(210 × 251 × 250 mm)
8.3 × 9.1 × 9.8 in
(210 × 230 × 250 mm)
Length × Width × Height
7.5 lbs (3.4 kg)
Dry weight
4-stroke, overhead valve, single cylinder
1.9 cu-in (31 cm )
Engine type
Displacement
[1.5 × 1.0 in (39 × 26 mm)]
1.5 bhp (1.10 kW, 1.5 PS) at 7,000 rpm
1.21 lbf·ft (1.64 N·m, 0.17 kgf·m) at 4,500 rpm
[Bore × Stroke]
Max. output
Max. torque
10,000 rpm
8,500 rpm
Max. rotation with no load
Fuel consumption
Cooling system
Ignition system
PTO shaft rotation
0.55 lb/hph (340 g/kWh, 250 g/PSh)
Forced air
Transistorized magneto
Counterclockwise
Tuneup
ITEM
SPECIFICATION
MAINTENANCE
0.024－0.028 in
(0.60－0.70 mm)
IN:0.12±0.02 mm
EX:0.15±0.02 mm
Spark plug gap
Refer to page: 31
Valve clearance (cold)
Other specifications
See your authorized
Honda dealer
No other adjustments needed.
53
TECHNICAL & CONSUMER INFORMATION
Wiring Diagram
Black
Ignition switch on the equipment
powered by the engine.
SPARK PLUG
IGNITION COIL
54
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.
55
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 46)
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
56
QUICK REFERENCE INFORMATION
Fuel
Type
Unleaded gasoline with a pump
octane rating of 86 or higher
(page 23)
GX22: 0.119 U S g a l
(0.45 , 0.099 Imp gal)
for horizontal types
0.159 U S g a l
Capacity
(0.60 , 0.132 Imp gal)
for vertical types
GX31: 0.172 U S g a l
(0.65 , 0.143 Imp gal)
for horizontal types
0.159 U S g a l
(0.60 , 0.132 Imp gal)
for vertical types
SAE 10W-30, API SJ, for general
use (page 28)
0.11 US qt (0.10 , 0.09 Imp qt)
NGK: CR5HSB
Engine Oil
Spark Plug
Type
Capacity
Type
DENSO: U16FSR-UB
0.024－0.028 in (0.60－0.70 mm)
(page 31)
Gap
Carburetor
Maintenance
Idle speed
Before
each use
3,100 ± 200 rpm
Check engine oil level.
Check air filter.
Check all bolts and nuts.
Change engine oil.
First 10
hours
Subsequent
Refer to the maintenance
schedule on page 21.
31ZM3613
2eY15000.2003.01
N
00X31-ZM3-6130
Printed in Japan
|