Honda SH300 2006 Manual page 503

TROUBLESHOOTING
ENGINE DOES NOT START OR IS HARD TO START
TROUBLESHOOTING
1. Spark Plug Inspection
Remove and inspect spark plug.
Is spark plug in good condition?
YES
NO
2. Spark Test
Perform spark test.
Is there weak or no spark?
YES
NO
3. Fuel Pump Inspection
You should hear the pump hum when the ignition switch is turned "ON".
Is the hum heard?
YES
NO
4. Cylinder Compression Inspection
Test the cylinder compression.
Is the compression within specification?
YES
NO
5. Fuel Flow Inspection
Inspect the fuel flow (page 6-48).
Is the fuel flow within specification?
YES
NO
6. Engine Start Condition
Start the engine by following the normal procedure.
Does the engine start but then stops?
YES
25-2
– GO TO STEP 2.
– • Plug not serviced frequently enough
• Incorrect spark plug heat range
• Incorrect spark plug gap
• Dirty air cleaner element
– • Faulty spark plug
• Fouled spark plug
• Opened or shorted spark plug wire
• Broken spark plug cap
• Broken or shorted ignition coil
• Faulty CKP sensor
• Loose or disconnected ignition system wires
• Faulty ECM
– GO TO STEP 3.
– GO TO STEP 4.
– • Broken fuel pump wire
• Faulty fuel pump
– GO TO STEP 5.
– • Valve stuck open
• Worn cylinder and piston rings
• Damaged cylinder head gasket
• Seized valve
• Incorrect valve seat contact
• Improper valve timing
– GO TO STEP 6.
– • Clogged fuel feed hose
• Faulty fuel pump
– • Inlet pipe leaking
• Improper ignition timing (faulty ECM or CKP sensor)
• Contaminated fuel
• Clogged IACV passage