I was running my Sportwerks 21 and it crapped out. When I went to start it back up it wouldnt stay running and when I did get it running it sounded different and when I gave it throttle it sounded like it was back firing. Whenever I try to give it WOT it just shuts off. I took it apart and only saw minor fragments but nothing that would bind the engine. Please tell me if I clean it out it will work like it use to.