| Engine will not start. | No mixture. |
| No ignition. | |
| No compression. | |
| Engine starts, but will not continue running. |
Clogged fuel pipe or strainer. |
| Air-bound tank or carburetor. | |
| Clogged exhaust. | |
| Wet spark plugs. | |
| Governor out of adjustment. | |
| Engine loses power. |
Retarded spark. |
| Poor compression. | |
| Overheating. | |
| Clogged exhaust. | |
| Incorrect mixture. | |
| Governor out of adjustment. | |
| Tight bearings. | |
| Dragging brake. | |
| Slipping clutch. | |
| Overloaded. | |
| Engine stops suddenly. | Ignition trouble. |
| Engine slows down and stops. |
Clogged fuel supply. |
| Incorrect Mixture. | |
| Overheated. | |
| Regular miss in one cylinder. |
Defective spark plug or wire. |
| Irregular miss in all cylinders. |
Sticking contact breaker. |
| Defective distributor. | |
| Clogged fuel line. | |
| Irregular fuel feed. | |
| Water in fuel. | |
| Faulty ignition connections. | |
| Engine runs unevenly. |
Incorrect spark plug gap. |
| Incorrect mixture. | |
| Binding carburetor float. | |
| Sticking valves. | |
| Sticking governor. | |
| Engine overheats. | Spark retarded. |
| Faulty cooling. | |
| Faulty lubrication. | |
| Engine smokes. | Black smoke; mixture too rich. |
| Blue smoke; too much oil. | |
| Broken or stuck piston rings. | |
| Poor oil. | |
| Engine backfires through carburetor. |
Mixture too lean. |
| Sticking inlet valve or weak inlet valve spring. |
|
| Explosions in exhaust pipe. |
Missing spark. |
| Mixture too rich. | |
| Sticking exhaust valve. | |