Hi, I have a 2001 Super Z with a 25hp Kawi on it. The engine only has about 55 hours on it. When I shut it down it backfires almost every time. I tried letting it idle for about 30-40 seconds before shutdown and it still backfires. I tried shutting down at 1/2 throttle, 3/4 throttle and full throttle....still back fires. Is this a problem I should get addresses? Can it result in harm to the engine? Any suggestions would be much appreciated. Thanks in advance.