SECTION 7 - ENGINE
7.1 ENGINE TROUBLESHOOTING
The following troubleshooting chart is to be used to isolate engine problems and give possible causes and corrective action responses.
The troubleshooting key is generic and can be used for several types of engines. Use only those possible causes and corrective actions that apply to the unit.
ENGINE TROUBLESHOOTING
PROBLEM | PROBABLE CAUSE | CORRECTION |
|
|
|
Black Exhaust | Restriction in air cleaner | Remove obstruction |
| Poor compression | Repair per instructions in manufacturer’s manual |
| Incorrect grade of fuel | Use fuel recommended in manufacturer’s manual |
| Leaking cylinder head gasket | Replace per instructions in manufacturer’s manual |
| Sticking valves | Repair per instructions in manufacturer’s manual |
| Worn cylinder bores | Repair per instructions in manufacturer’s manual |
| Pitted valves and seats | Repair per instructions in manufacturer’s manual |
| Broken, worn, or sticking piston rings | Repair per instructions in manufacturer’s manual |
|
|
|
Blue/White Exhaust | Incorrect grade of lubricating oil | Use oil recommended in manufacturer’s manual |
| Poor compression | Repair per instructions in manufacturer’s manual |
| Leaking cylinder head gasket | Replace per instructions in manufacturer’s manual |
| Worn cylinder bores | Repair per instructions in manufacturer’s manual |
| Worn valve stem guides | Repair per instructions in manufacturer’s manual |
| Broken, worn, or sticking piston rings | Repair per instructions in manufacturer’s manual |
|
|
|
Difficult Starting | Restriction in air cleaner | Remove obstruction |
| Low cranking speed | Check connections to electric start (if applicable) |
| Controls not in correct operating position | Reset controls |
| Blocked fuel feed line | Remove obstruction |
| Choked fuel filter | Clean or replace filter |
| 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 valves | 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 |
|
|
|
Erratic Running | Restriction in air cleaner | Remove obstruction |
| Controls not in correct operating position | Reset controls |
| Blocked fuel feed line | Remove obstruction |
| Choked fuel filter | Clean or replace filter |
| Poor compression | Repair per instructions in manufacturer’s manual |
| Blocked fuel tank vent | Remove obstruction |
| Sticking throttle/restricted movement | Lubricate or replace |
| Overheating | Allow to cool; determine cause |
| Sticking valves | Repair per instructions in manufacturer’s manual |
| Broken, worn, or sticking piston rings | Repair per instructions in manufacturer’s manual |
| Broken valve spring | Repair per instructions in manufacturer’s manual |
| Bad spark plugs | Install new spark plugs |
7 - 22