backfire

[Sharp153]

My Briggs and Stratton 14.5 horse OHV Model 287707, Type 022501, Code 9408104A on a Murray mower blows back into the carburetor intermittently. It starts and runs, but intermittently blows back into the carb. Once when I had the air filter off it flamed when it blew back. What is the cause and correction?

 

[Rivets]

Two things that I would check. First drain the gas, I think that you may have water contamination. Second check your valve clearances.