I have an old old briggs and straton engine on my mower idle is terrable and backfires on acceleration?????????????

dennis sisko, April 2008

Backfires are nearly always due to the fuel mixture being somewhat weak....you don't say which engine you have, but if there's one spring loaded screw on the carb, run the engine as fast as it will go - undo the screw until the engine falters and produces black smoke (take your time here) then turn the screw back in until the engine runs smoother.

John, April 2008