Why is my lawn mower making a popping sound?
Likewise, people ask, why is my lawn mower engine popping?
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.
Similarly, why does my lawn mower pop when I turn it off?
Backfire, or more accurately "after fire" when it occurs when stopping an engine, is caused by unburned fuel/air mixture being ignited by the heat of the muffler. Allowing the engine to idle from 30-60 seconds before turning the key to the OFF position will generally prevent this after fire condition.
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.