Small Engines (Lawn Mowers, etc.): backfiring engine, minor tune, intec

Question
i have a B&S 25 HP intec I/C platinum engine on a craftsman rider. Its 8 years old. It backfires very loud and seems to do it at all speeds while running. I've done a minor tune up on it several times and took it to a shop but it still does it. Any ideas? Thanks
Model # according to sears 4455777-0154-e1

Answer
Carmen

Sounds like you have a timing problem or the valves are out of adjustment. I would bring it back to the shop and have them fix it right. Check to make sure your flywheel key didn't get damaged and that the coil is putting out.When ever a engine back fires at high speed it is usually a timing problem.