PJ - I asked this at the beginning of the season with no solution found so I wanted to see if there have been any new solutions. My 24hp Honda is backfiring on shut down on my Super Z...it's really loud and only does it when it's warm. I took it to the dealer and they tried adjusting the carb but nothing seems to work. The muffler is really rusty for some reason and may have some pin holes in it, could this be thre reason due to some back pressure issue? None of my other Hustlers (2) have had this issue but they have had the Kawasaki's. Any suggestions?? I'm tired of scaring anyone within a 2 block radius when I shut it down on the trailer. And yes I have tried EVERY possible shut down scenario including with the throttle including idling at the lowest and/or half throttle for a long time before shutting it off. I have had plenty of other machines with every engine out there and have never had this issue...I'm frustrated and puzzled.