What is the cause of a firecracker sound when starting a lawnmower?

Question

Toro riding mower, Briggs & stratton engine, about 10 years old in good shape otherwise, will not turn over since the pop sound.

Answer

My first guess is faulty ignition. Raw gas is expelled into the muffler. A second stroke gets a spark and the gas in the muffler explodes. I have seen mufflers split because of this.

What is the cause of a firecracker sound when starting a lawnmower?

Answers (1)