You are just mowing along and your engine suddenly backfires and then it starts to continue running like normal. What could be causing this and how do I resolve it?
An engine backfire can be caused by an electrical problem or a mechanical one. In most cases it can be tracked down to an electrical problem, more specifically in the ignition system. If the ignition coil becomes too hot or has an internal breakdown, the spark will become intermittent and the combustion chamber can be ignited at the wrong time and cause a backfire out of the intake or exhaust.
The ignition kill wire could also have been compromised and partially broken because of rodent damage or heat and vibration. So you want to check it and is usually a black or gray wire that is attached to the ignition coil.
There could also be a problem with the ignition switch.
If the ignition system is working normally, then the search begins on the mechanical portion of the engine. A leak down test will need to be performed initially to determine if the intake or the exhaust valve is leaking. If one of them is leaking, the burning gasses will pass through them and cause a backfire while the engine is running and particularly under a load such as cutting the grass.
If you need a lawn mower repair shop near you to fix your mower, visit our Locations page for assistance.