I have a Craftsman LT1000 Briggs and Stratton 20H.P. V-Twin cylinder 42" cut, electric start, 6 speed manual riding mower.
It backfires thru exhaust every few minutes but runs o'k otherwise
I replaced air filter, plugs, fuel filter and cracked gas line - didn't help.
Is this due to late ignition and can be fixed by adjusting timing or should I look elsewhere?

Mike C., May 2009

Check the intake pipes for leaks and the o rings in the flanges, i removed the plastic runners and sealed the seams with polyurethane calk and cured the backfire.
i think it should have been designed with more flexable
connection from carb to cyls.
Dennis in Chicago

Dennis in Chicago, May 2009

It may be the ignition, but it may also be the carburetor running a little rich....!

Tony, May 2009