ENGINE TROUBLESHOOTING
PROBLEM | PROBABLE CAUSE | CORRECTION |
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Excessive Fuel | Restriction in air cleaner | Remove obstruction |
Consumption | Poor compression | Repair per instructions in manufacturer’s manual |
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| Incorrect grade of fuel | Use fuel recommended in manufacturer’s manual |
| Sticking throttle/restricted movement | Lubricate or replace |
| Leaking cylinder head gasket | Repair per instructions in manufacturer’s manual |
| Worn oil pump | Repair per instructions in manufacturer’s manual |
| Worn cylinder bores | Repair per instructions in manufacturer’s manual |
| Pitted valve stems and seats | Repair per instructions in manufacturer’s manual |
| Broken, worn, or sticking piston rings | Repair per instructions in manufacturer’s manual |
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High Oil Pressure | Incorrect grade of lubricating oil | Use oil recommended in manufacturer’s manual |
| Pressure relief valve sticking closed | Repair or replace spring |
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Knocking | Incorrect grade of fuel | Use fuel recommended in manufacturer’s manual |
| Overheating | Allow to cool; determine cause |
| Sticking valves | Repair per instructions in manufacturer’s manual |
| Worn cylinder bores | Repair per instructions in manufacturer’s manual |
| Broken, worn, or sticking piston rings | Repair per instructions in manufacturer’s manual |
| Worn or damaged bearings | Repair per instructions in manufacturer’s manual |
| Incorrect piston height | Adjust per instructions in manufacturer’s manual |
| Broken valve spring | Replace per instructions in manufacturer’s manual |
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Loss of Power or System | Restriction in air cleaner | Remove obstruction |
| Blocked fuel feed line | Remove obstruction |
| Choked fuel filter | Remove obstruction |
| Poor compression | Repair per instructions in manufacturer’s manual |
| Blocked fuel tank vent | Remove obstruction |
| Incorrect grade of fuel | Use fuel recommended in manufacturer’s manual |
| Sticking throttle/restricted movement | Lubricate or replace |
| Leaking cylinder head gasket | Replace per instructions in manufacturer’s manual |
| Overheating | Allow to cool; determine cause |
| Worn cylinder bores | Repair per instructions in manufacturer’s manual |
| Pitted valve stems and seats | Repair per instructions in manufacturer’s manual |
| Broken, worn, or sticking piston rings | Repair per instructions in manufacturer’s manual |
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Low Cranking Power | Bad electrical connection | Check connections to electric start (if applicable) |
| Faulty starter motor (if applicable) | Replace per instructions in manufacturer’s manual |
| Incorrect grade of lubricating oil | Use oil recommended in manufacturer’s manual |
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Low Oil Pressure | Incorrect grade of lubricating oil | Use oil recommended in manufacturer’s manual |
| Worn or damaged bearings | Replace per instructions in manufacturer’s manual |
| Insufficient oil in sump | Refill with oil |
| Oil pump worn | Replace per instructions in manufacturer’s manual |
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Misfiring | Choked fuel filter | Remove obstruction |
| Poor compression | Repair per instructions in manufacturer’s manual |
| Leaking cylinder head gasket | Replace per instructions in manufacturer’s manual |
| Overheating | Allow to cool; determine cause |
| Incorrect tappet adjustment | Adjust per instructions in manufacturer’s manual |
| Sticking valves | Repair per instructions in manufacturer’s manual |
| Pitted valves and seats | Repair per instructions in manufacturer’s manual |
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Overheating | Restriction in air cleaner | Remove obstruction |
| Incorrect valve timing | Adjust per instructions in manufacturer’s manual |
| Leaking cylinder head gasket | Replace per instructions in manufacturer’s manual |
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