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.
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.
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.
CONTENTS ENGINE SAFETY IMPORTANT SAFETY INFORMATION CONTROLS & FEATURES COMPONENT & CONTROL LOCATIONS CONTROLS Choke Lever Throttle Lever Recoil Starter Grip FEATURES Centrifugal Clutch BEFORE OPERATION IS YOUR ENGINE READY TO GO? Check the General Condition of the Engine Check the Engine Check the Equipment Powered by This Engine OPERATION SAFE OPERATING PRECAUTIONS...
CONTENTS HELPFUL TIPS & SUGGESTIONS STORING YOUR ENGINE Storage Preparation Storage Precautions Removal From Storage TRANSPORTING TAKING CARE OF UNEXPECTED PROBLEMS ENGINE WILL NOT START ENGINE LACKS POWER TECHNICAL & CONSUMER INFORMATION TECHNICAL INFORMATION Serial Number Location Remote Control Linkage Carburetor Modification for High Altitude Operation Oxygenated Fuels Emission Control System Information...
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.
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.
CONTROLS & FEATURES COMPONENT & CONTROL LOCATIONS Horizontal type: AIR CLEANER PRIMING BULB FUEL FILLER CAP FUEL TANK Vertical type: SPARK ARRESTER MUFFLER (inside the cover) SPARK PLUG CHOKE LEVER SPARK PLUG CHOKE LEVER RECOIL STARTER OIL FILLER CAP RECOIL STARTER STARTER GRIP PRIMING BULB AIR CLEANER...
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.
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.
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.
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.
Check the Engine Check the engine oil level (see page low oil level can cause engine damage. Check the air filter (see page 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.
OPERATION SAFE OPERATING PRECAUTIONS Before operating the engine for the first time, please review the IMPORTANT SAFETY INFORMATION on page 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.
Press the priming bulb repeatedly until fuel can be seen in the clear- plastic fuel-return tube. PRIMING BULB Turn the ignition switch to the ON position. Pull the starter grip lightly until you feel resistance, then pull briskly. Return the starter grip gently. Horizontal type: STARTER GRIP Vertical type:...
OPERATION 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 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.
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. 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.
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.
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.
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...
SERVICING YOUR HONDA ENGINE REFUELING Fuel tank capacities GX22: 0.119 US gal (0.45 , 0.099 Imp gal) 0.159 US gal (0.60 , 0.132 Imp gal) GX31: 0.172 US gal (0.65 , 0.143 Imp gal) 0.159 US gal (0.60 , 0.132 Imp gal) Check the fuel level by looking through the translucent fuel tank.
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.
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.
SERVICING YOUR HONDA ENGINE Reinstall the oil filler cap/dipstick securely. Running the engine with a low or excessive oil level can cause engine damage.
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. Check that the fuel tank cap is tightened securely.
SERVICING YOUR HONDA ENGINE 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: Running the engine with a low or excessive oil level can cause engine damage.
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.
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.
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. Clean the air filter in warm soapy water, rinse, and allow to dry thoroughly.
SERVICING YOUR HONDA ENGINE SPARK PLUG SERVICE Recommended spark plug: An incorrect spark plug can cause engine damage. Disconnect the spark plug cap, and remove any dirt from around the spark plug area. Remove the spark plug with a 5/8-inch spark plug wrench. SPARK PLUG CAP Inspect the spark plug.
SERVICING YOUR HONDA ENGINE 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.
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 COOLING FINS (inside the cover)
SERVICING YOUR HONDA ENGINE FUEL FILTER INSPECTION and FUEL TANK CLEANING Check that the engine oil filler cap is tightened securely. 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.
SERVICING YOUR HONDA ENGINE 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. Inspect the fuel filter. If the fuel filter is dirty, wash it gently with nonflammable or high flashpoint solvent.
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.
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. Remove the air cleaner cover (see page 29). 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.
SERVICING YOUR HONDA ENGINE Remove the two 5 mm bolts from the top cover, and remove the top cover. × 22 mm BOLTS Remove the three 5 mm screws from the muffler cover, and remove the muffler cover. Remove the 4 mm screw from the spark arrester, and remove the spark arrester from the muffler.
SERVICING YOUR HONDA ENGINE 7. 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 Install the spark arrester, muffler cover, top cover, and recoil starter in the reverse order of disassembly.
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.
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.
HELPFUL TIPS & SUGGESTIONS DRAINING THE FUEL TANK AND CARBURETOR Remove the fuel tank cap and drain the fuel into an approved gasoline container by tipping the engine toward the fuel filler neck. Press the priming bulb several times until there is no more fuel in the fuel return tube.
Engine Oil Change the engine oil (see page 26). Remove the spark plug (see page 31). Pour a teaspoon (1 3 cc) of clean engine oil into the cylinder. − Pull the starter rope several times to distribute the oil in the cylinder. Reinstall the spark plug.
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.
TAKING CARE OF UNEXPECTED PROBLEMS ENGINE WILL NOT START Check control positions. Check fuel. Remove and inspect spark plug. Take engine to an authorized Honda servicing dealer, or refer to shop manual. ENGINE LACKS POWER Check air filter. Check fuel. Take engine to an authorized Honda servicing dealer, or...
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 Engine serial number:...
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 ) for access to the throttle lever and cable fitting. CABLE ATTACHMENT FITTING THROTTLE CABLE...
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.
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.
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.
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).
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.
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.
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.