The noise Generally is heard when the engine is under load, Such as when
accelerating or climbing a hill.While it often may be caused by a tankful of inferior gas, ignition
knock frequently is a sign your engine needs attention.It also can be caused by a build-up of carbon
inside the engine.
Late model cars are equipped with a knock sensor which "hears" the sound and makes corrective adjustment. But it cannot compensate for a severe malfunction,a condition which can affect engine performance, even damage the engine.
| Cause | Remedy |
| Carbon in combustion chamber | Remove cylinder head and clean carbon from head and piston |
| Loose or worn connecting rod | Replace connecting rod |
| Loose flywheel | Check flywheel key and keyway; replace parts if nessary. Tighten flywheel nut |
| Loose blade | tighten blade |
| Worn cylinder and piston | Replace cylinder and piston as a unit |
| Most probable cause | |
|
|
Note :- The most common complaint of engine knocking is in fact the blade
not tight enough. The blade can come loose very easily and is one
component on a lawnmower or ride-on that must always be maintained.
