Honda 2005 FOURTRAX FOREMAN TRX500 TM Service Manual page 442

TROUBLESHOOTING
ENGINE DOES NOT START OR IS HARD TO START
1. Fuel Flow Inspection
Check fuel flow to the carburetor.
Is fuel reaching the carburetor?
NO - • Clogged fuel line and strainer
• Clogged fuel valve
• Clogged fuel tank breather hose
YES - GO TO STEP 2.
2. Spark Plug Inspection
Remove and inspect the spark plug.
Is the spark plug wet with fuel?
YES - • Flooded carburetor
• Throttle valve open
• Dirty air cleaner
• Improperly adjusted pilot screw
• Starting enrichment (SE) valve stuck open or damaged
NO - GO TO STEP 3.
3. Spark Test
Perform the spark test.
Is the spark quality good?
NO - • Faulty spark plug
• Fouled spark plug
• Loose or disconnected ignition system wires
• Broken or shorted spark plug wire
• Faulty ignition coil
• Faulty ignition pulse generator
• Faulty engine stop switch
• Faulty ignition switch
• Faulty ignition control module (ICM)
YES - GO TO STEP 4.
4. Engine Start Condition
Start the engine by following the normal procedure.
Does the engine start but stop?
YES - Improper choke operation
Incorrectly adjusted carburetor
Leaking carburetor insulator
Improper ignition timing (Faulty ECM or ignition pulse generator)
Contaminated fuel
NO - GO TO STEP 5.
5. Cylinder Compression Inspection
Test the cylinder compression.
Is the compression as specified?
NO -
Valve clearance too small
Valve stuck open
Worn cylinder and piston rings
Damaged cylinder head gasket
Seized valve
Improper valve timing
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