Troubleshooting Guide
ENGINE DOES NOT START OR HARD TO START
What To Check
Vaporlock.
Possible Cause
Engine hot/heat soaked.
Low fuel quality.
Remedy
Let cool completely and restart.
Refill with fresh, clean unleaded gasoline with a pump octane of 87 or higher mixed with a
Valve adjustment.
Valve clearance too tight. Valve clearance too loose.
Adjust valves. See page 10.
What To Check
Does the engine crank?
YES
Good compression?
YES
Does the tank contain fresh fuel of the proper grade?
YES
Is fuel visible and moving in the return line when priming?
YES
Is there spark at the spark plug wire terminal?
YES
Check the spark plug.
NO
NO
NO
NO
NO
ENGINE DOES NOT START
Possible Cause
Faulty recoil starter.
Fluid in the crankcase.
Internal damage.
Loose spark plug.
Excess wear on cylinder, piston, rings.
Fuel incorrect, stale, or contaminated; mixture incorrect.
Check for clogged fuel filter and/or vent.
The ignition switch is in “O” (OFF) position. Shorted ignition ground.
Faulty ignition unit.
If the plug is wet, excess fuel may be in the cylinder.
The plug is fouled or improperly gapped.
The plug is damaged internally or of the wrong size.
Remedy
Consult with an authorized servicing dealer.
Tighten and
Consult with an authorized servicing dealer.
Refill with fresh, clean unleaded gasoline with a pump octane of 87 or higher mixed with a
Clean as required. Restart.
Move switch to “I” (ON) position and
Consult with an authorized servicing dealer.
Crank the engine with the plug removed, reinstall the plug, and restart.
Clean and regap the plug to 0.6 mm. Restart.
Replace the spark plug with a NGK CMR5H or equivalent spark plug of the correct heat range. Adjust the spark plug electrode gap to 0.6 - 0.7 mm.
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