Lot more interesting detail can be read here. Correspondingly, why is my lawnmower backfiring?
A spark plug that is damaged, worn, or has an improperly set gap between its electrodes creates a weak spark. As a result, the fuel may not ignite in the cylinder, but it might ignite when it reaches the hot exhaust muffler. The result is a loud backfire. Poor spark also results in a mower that runs unreliably.
Beside above, what happens when a lawn mower backfires? Backfires occur when burning fuel enters the engine or the exhaust. If pockets of unspent fuel enter the engine before the valves close or escape to the exhaust system, a backfire occurs. Unspent fuel ignites when a spark occurs in close proximity to the fuel pocket.
Secondly, why is my Briggs and Stratton backfiring?
Shutting off the engine at high RPM, causing fuel to pump through the engine for ignition. Gasoline that contains alcohol has a tendency to ignite easier, which can cause afterfire. Small engine muffler type and manufacture. Carburetor adjustment may not be properly set for correct engine performance.
What causes lawn mower to rev up and down?
A carburetor that's incorrectly adjusted is a common cause of poor engine idling that results in hunting and surging. Fortunately, most lawnmowers have two screws that allow you to adjust the carburetor yourself. Then slowly adjust the screws tighter or looser in turn until the mower runs and idles smoothly.
