Home / Small Engines / Honda Engines / Honda GX340

Honda GX340 Troubleshooting

Engine Model: Honda GX340
Engine Type: 4-cycle OHV 1-cylinder gasoline engine
Total Displacement: 20.6 (337 cc)
Rated Engine Power: 11 Hp (8.2 kW) at 3600 rpm
Carburetor Type: Horizontal, butterfly valve


Engine starts hard or won't start

No gasoline in tank - Fill it up.
Wrong grade of gasoline - Use quality fuel.
Water or air in fuel system - Remove air or water from system.
Spark plug wire is loose or disconnected - Check the spark plug wire connection, repair or replace.
Defective spark plug - Replace spark plug.
Plugged fuel filter - Replace fuel filter.
Safety contact for brake pedal defective - Install new part.
Carburetor problems - Carburetor diagnostics required.
Engine has low compression - Check cylinder block and replace defective parts.
Incorrectly adjusted or damaged throttle cable - Adjust correctly or replace the cable.

Rough engine running

Cooling fins are blocked - Wash or clean as required.
Ignition system malfunction - Check ignition and replace faulty components.
Stuck or faulty choke cable - Replace or clean the cable.
Plugged air filter - Service or replace air filter.
Clogged or damaged fuel pump - Clean or install new fuel pump.

Engine starts and then shuts off

Spark plug is damaged - Change spark plug as required.
Dirty or defective carburetor - Service or repair carburetor.
Faulty ignition coil - Ignition coil must be replaced.
Weak or damaged valve springs - Replace valve springs.
Valves sticking - Valves need to be cleaned.

Engine is overheated

Low engine oil level - Check oil level and add oil as required.
Engine overloaded - Reduce engine load.
Clogged cooling fins - Wash or clean as required.
Too lean carburetor mixture - Adjust carburetor correctly.
Bad ignition timing - Set the ignition timing correctly.
Valve setting is improper - Valves needs to be set correctly.

Abnormal engine noise or knocking

Stale fuel - Use correct fuel.
Excessive engine load - Load reducing is recommended.
Engine oil level low - Check oil level and add oil as required.
Low idle speed setting is incorrect - Adjustment required.
Fuel pump is defective or dirty - Inspect fuel pump and change as required.
Main bearings or crankshaft wear - Repair or replace defective parts.
Valve clearance is improper - Adjust valve clearance according to specifications.
Worn piston rings or cylinder bore - Change faulty components.

Engine power is too low

Carburetor is incorrectly adjusted or dirty - Clean or correctly adjust carburetor.
Air filter is dirty - Change or service air filter.
Clogged or defective fuel pump - Check fuel pump and replace if necessary.
Defective ignition - Inspect ignition system and change failed components.
Cylinder head gasket is damaged - Replace the head gasket.
Burned or stuck valves - Change or clean valves.
Push rod is worn or damaged - Push rod needs to be changed.
Faulty cylinder block parts - Replace defective components.
Clogged oil filter (if equipped) - Service or change oil filter.

High fuel consumption

Throttle is not fully open - Change or adjust throttle cable.
Incorrect carburetor main jet adjustment - Adjust it properly.
Loose or defective spark plug - Spark plug need to be tightened or replaced.
Valves are worn, burned or stuck - Clean or replace valves.
Sleeve, piston, or rings are damaged - Change faulty parts.
Valve clearance is not correct - Adjust to proper valve clearance.

Excessive engine oil consumption

Worn gaskets or seals - To repair leaks, replace worn parts.
Valve stems or guides are damaged - Install new valves.
Worn or stuck piston rings - Have piston rings replaced.
Piston or cylinder liner is scored - Check piston and liner, install new parts as required.
Breather pipe or hose is blocked - Service or replace.