Today towards the end of the day my dixie chopper w/20hp or 22hp kohler was backfiring like one after the other . If this a sign of engine trouble what can i do to prevent it or check it out. It sounds like the mufler is exploding over and over.Also my lucknuts came of today too. Wow got to watch out for those. Didnt even notice till my wheel was wobbling. But today was my first day on the chopper for a long time. God bless.