Owner’s Manual GX240 GX270 GX340 GX390 • • • o2003 Honda Motor Co., Ltd. -All Rights Reserved...
Illustrations are based on the GX270. Only certain types are equipped for both electric and manual starting. 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.
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.
INTRODUCTION A FEW WORDS ABOUT SAFETY Your safety and the safety of others is 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 .................... Fuel Valve Lever ................Engine Switch ..................Choke Lever ..................10 Throttle Lever .................. . 11 Recoil Starter Grip ................
CONTENTS SERVICING YOUR ENGINE (continued) SEDIMENT CUP CLEANING ..............36 SPARK PLUG SERVICE ............... . 37 IDLE SPEED ADJUSTMENT ..............38 SPARK ARRESTER MAINTENANCE (optional equipment) ....39 HELPFUL TIPS & SUGGESTIONS ............40 STORING YOUR ENGINE ..............
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 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.
CONTROLS & FEATURES COMPONENT & CONTROL LOCATIONS MUFFLER THROTTLE LEVER AIR CLEANER ENGINE SWITCH SPARK PLUG (applicable types only) CIRCUIT BREAKER (applicable types only) CHOKE LEVER RECOIL STARTER FUEL VALVE LEVER Internal vent carburetor STARTER GRIP type (with TUBE CLIP) FUEL FILLER CAP BREATHER TUBE FUEL TANK...
CONTROLS & FEATURES CONTROLS Fuel Valve Lever The fuel valve opens and closes the passage between the fuel tank and the carburetor. The fuel valve lever must be in the ON position for the engine to run. When the engine is not in use, leave the fuel valve lever in the OFF position to prevent carburetor flooding and to reduce the possibility of fuel leakage.
CONTROLS & FEATURES 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. ALL ENGINES EXCEPT ELECTRIC STARTER TYPES ELECTRIC STARTER TYPES ENGINE SWITCH...
CONTROLS & FEATURES Choke Lever or Choke Rod (applicable types) The choke lever or choke rod (applicable types) 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.
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 remote-mounted throttle control rather than the engine-mounted throttle lever shown here. THROTTLE LEVER SLOW Recoil Starter Grip...
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).
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.
BEFORE OPERATION Check the Engine Check the engine oil level (see page ). 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.
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.
OPERATION To start a cold engine, move the choke lever or choke rod (applicable types) to the CLOSED position. To restart a warm engine, leave the choke lever in the OPEN position. Some engine applications use a remote-mounted choke control rather than the engine-mounted choke lever shown here.
OPERATION Turn the engine switch to the ON position. ALL ENGINES EXCEPT ELECTRIC STARTER TYPES ELECTRIC STARTER TYPES ENGINE SWITCH Operate the starter. RECOIL STARTER (all engine types): Pull the starter grip lightly until you feel resistance, then pull briskly. Return the starter grip gently.
OPERATION ELECTRIC STARTER (applicable types only): Turn the key to the START position, and hold it there until the engine starts. If the engine fails to start within 5 seconds, release the key, and wait at least 10 seconds before operating the starter again.
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. Move the throttle lever to the SLOW position. Some engine applications use a remote-mounted throttle control rather than the engine-mounted throttle lever shown here.
OPERATION Turn the fuel valve lever to the OFF position. FUEL VALVE LEVER SETTING ENGINE SPEED Position the throttle lever for the desired engine speed. Some engine applications use a remote-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.
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.
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...
SERVICING YOUR ENGINE MAINTENANCE SCHEDULE REGULAR SERVICE PERIOD (3) First Every Every Every ITEM Refer Each month 3 months 6 months year Perform at every indicated month or operating hour interval, page 20 Hrs. 50 Hrs. 100 Hrs. 300 Hrs. whichever comes first.
SERVICING YOUR ENGINE REFUELING With the engine stopped and on a level surface, remove the fuel tank cap and check the fuel level. Refill the tank if the fuel level is low. Gasoline is highly flammable and explosive. You can be burned or seriously injured when handling fuel.
SERVICING YOUR 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 ENGINE ENGINE OIL LEVEL CHECK Check the engine oil level with the engine stopped and in a level position. Remove the filler cap/dipstick and wipe it clean. Insert and remove the dipstick without screwing it into the filler neck. Check the oil level shown on the dipstick.
SERVICING YOUR ENGINE ENGINE OIL CHANGE Drain the used oil while the engine is warm. Warm oil drains quickly and completely. Place a suitable container below the engine to catch the used oil, then remove the filler cap/dipstick, drain plug, and washer. Allow the used oil to drain completely, then reinstall the drain plug, washer, and tighten drain plug securely.
SERVICING YOUR 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 ENGINE TRANSMISSION OIL LEVEL CHECK (applicable engine types) Check the transmission oil level with the engine stopped and in a level position. 2 : 1 Reduction Transmission With Centrifugal Clutch Remove the filler cap/dipstick and wipe it clean. Insert and remove the dipstick without screwing it into the filler hole.
SERVICING YOUR ENGINE TRANSMISSION OIL CHANGE (2 : 1 reduction transmission with centrifugal clutch) Drain the used oil while the engine is warm. Warm oil drains quickly and completely. Place a suitable container below the transmission to catch the used oil, then remove the filler cap/dipstick and the drain plug.
SERVICING YOUR ENGINE AIR FILTER INSPECTION Remove the air cleaner cover and inspect the filter. Clean or replace dirty filter elements. Always replace damaged filter elements. If equipped with an oil-bath air cleaner, also check the oil level. Refer to pages 32 35 for instructions that apply to the air cleaner and filter on your type of engine.
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.
SERVICING YOUR ENGINE Paper air filter element: Tap the filter element several times on a CYCLONE DUAL-FILTER-ELEMENT TYPE hard surface to remove dirt, or blow compressed air [not PRECLEANER CAP AIR CLEANER COVER exceeding 30 psi (207 kPa, 2.1 kgf/cm )] through the filter SPECIAL PAN SCREW (3) element from the inside.
OIL BATH TYPE ONLY: Fill the air cleaner case to the OIL LEVEL mark with the same oil that is recommended for the engine (see page 28). Oil capacities GX240/GX270: 2.0 US oz (60 cm ) GX340/GX390: 2.7 US oz (80 cm ) Reassemble the air cleaner, and tighten the wing nut securely.
SERVICING YOUR ENGINE Low Profile Types AIR CLEANER COVER CLIP Unsnap the air cleaner cover clips, remove the air cleaner cover, and remove the element. Wash the air filter in a solution of household detergent and warm water, then rinse thoroughly, or wash in nonflammable or high flashpoint solvent.
SERVICING YOUR ENGINE SEDIMENT CUP CLEANING Move the fuel valve to the OFF position, then remove the fuel sediment cup and O-ring. 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.
SERVICING YOUR ENGINE SPARK PLUG SERVICE Recommended spark plugs: BPR6ES (NGK) W20EPR-U (DENSO) 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 13/16-inch spark plug wrench. SPARK PLUG WRENCH Inspect the spark plug.
SERVICING YOUR ENGINE After the spark plug seats, tighten with a 13/16-inch spark plug wrench to compress the sealing 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 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.
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 after storage. Cleaning If the engine has been running, allow it to cool for at least half an hour before cleaning.
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.
HELPFUL TIPS & SUGGESTIONS DRAINING THE FUEL TANK AND CARBURETOR Place an approved gasoline container below the carburetor, and use a funnel to avoid spilling fuel. Remove the carburetor drain bolt and sediment cup, then move the fuel valve lever to the ON position. Gasoline is highly flammable and explosive.
HELPFUL TIPS & SUGGESTIONS Engine Oil Change the engine oil (see page 27 ). Engine Cylinder Remove the spark plug (see page 37 ). Pour a tablespoon (5 10 cc) of clean engine oil into the cylinder. Pull the starter rope several times to disribute the oil in the cylinder. Reinstall the spark plug.
HELPFUL TIPS & SUGGESTIONS Position the equipment so the engine is level. Tilting can cause fuel or 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.
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 Possible Cause Correction START Electric starting Battery discharged. Recharge battery: (applicable types): Fuse burnt out. Replace fuse (p. 47). Check battery and fuse. Check control Fuel valve OFF. Move lever to ON. positions.
TAKING CARE OF UNEXPECTED PROBLEMS FUSE REPLACEMENT (applicable types only) The electric starter relay circuit and battery charging circuit are protected by a 5-ampere fuse. If the fuse burns out, the electric starter will not operate. The engine can be started manually if the fuse burns out, but running the engine will not charge the battery.
TECHNICAL & CONSUMER INFORMATION TECHNICAL INFORMATION Serial Number Location ELECTRIC STARTER (applicable types only) 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 Battery Connections for Electric Starter (applicable types only) Use a 12-volt battery with an ampere-hour rating of at least 18 Ah. Be careful not to connect the battery in reverse polarity, as this will short circuit the battery charging system. Always connect the positive ( ) battery cable to the battery terminal before connecting the negative ( ) battery cable, so your tools cannot cause a short circuit if they touch a grounded part while tightening the positive ( ) battery...
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.
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 plugs 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 Specifications GX240/GX270 14.0 16.9 16.1 in Length Width Height (355 410 mm) 55.1 lbs (25.0 kg) Dry weight 4-stroke, overhead valve, single cylinder Engine type 14.8 cu-in (242 cm ) Displacement GX240 2.3 in (73 58 mm)
TECHNICAL & CONSUMER INFORMATION GX240/GX270/GX340/GX390 Tuneup ITEM SPECIFICATION MAINTENANCE 0.028 0.031 in Spark plug gap Refer to page: 37 (0.70 0.80 mm) 1,400 150 rpm Idle speed Refer to page: 38 0.15 0.02 mm (cold) Valve clearance See your authorized 0.20...
TECHNICAL & CONSUMER INFORMATION Wiring Diagrams Oil Alert and Electric Starter Types Engine Types With Oil Alert and Without Electric Starter...
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.
If you are still dissatisfied after speaking with the Regional Engine Distributor, you may 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...
QUICK REFERENCE INFORMATION Fuel Type Unleaded gasoline with a pump octane rating of 86 or higher (page 25). Engine Oil Type SAE 10W-30, API SJ or SL, for general use (page 28) Spark Plug Type NGK: BPR6ES DENSO: W20EPR-U 0.028 0.031 in (0.70 0.80 mm) (page 37) Carburetor Idle speed...
2eY150000.2003.10 31ZH9621 00X31-ZH9-6210 Printed in Japan...