Harbor Freight Tools 68375 manual Use Engine will not start, Compression Related section

Engine Troubleshooting (cont.)

Problem		Possible Causes		Probable Solutions
Engine misfires	1. Spark plug cap loose.		1.	Check wire connections.
	2.	Incorrect spark plug gap or	2.	Re-gap or replace spark plug.
		damaged spark plug.
	3.	Defective spark plug cap.	3.	Replace spark plug cap.
	4.	Old or low quality gasoline.	4.	Use only fresh 87+ octane unleaded gasoline.
				Do not use gasoline with more than
				10% ethanol (E15, E20, E85, etc.).
	5.	Incorrect compression.	5.	Diagnose and repair compression.
				(Use Engine will not start:
				Compression Related section.)
Engine stops	1.	Low oil shutdown.	1.	Fill engine oil to proper level. Check
suddenly				engine oil before EVERY use.
	2.	Fuel tank empty or full of impure or low	2.	Fill fuel tank with fresh 87+ octane
		quality gasoline.		unleaded gasoline.
				Do not use gasoline with more than
				10% ethanol (E15, E20, E85, etc.).
	3.	Defective fuel tank cap creating	3.	Test/replace fuel tank cap.
		vacuum, preventing proper fuel flow.
	4.	Faulty magneto.	4.	Have qualified technician service magneto.
	5.	Disconnected or improperly	5.	Secure spark plug cap.
		connected spark plug cap.
Engine stops when	1. Dirty air filter		1.	Clean or replace element.
under heavy load	2. Engine running cold.		2.	Allow engine to warm up prior
				to operating equipment.
Engine knocks	1.	Old or low quality gasoline.	1.	Fill fuel tank with fresh 87+ octane
				unleaded gasoline.
				Do not use gasoline with more than
				10% ethanol (E15, E20, E85, etc.).
	2.	Engine overloaded.	2.	Do not exceed equipment’s load rating.
	3.	Incorrect spark timing, deposit	3.	Have qualified technician diagnose
		buildup, worn engine, or other		and service engine.
		mechanical problems.
Engine backfires	1.	Impure or low quality gasoline.	1.	Fill fuel tank with fresh 87+ octane
				unleaded gasoline.
				Do not use gasoline with more than
				10% ethanol (E15, E20, E85, etc.).
	2.	Engine too cold.	2.	Use cold weather fuel and oil
				additives to prevent backfiring.
	3.	Intake valve stuck or overheated engine.	3.	Have qualified technician diagnose
				and service engine.
	4.	Incorrect timing.	4.	Check engine timing.

Follow all safety precautions whenever diagnosing or servicing the equipment or engine.

Item 68375	For Pump technical questions, please call 1-800-444-3353.	Page 17
	For Engine technical questions, please call 1-800-520-0882.