My K5 doesn't run as well as I really think it could or should with the brand new rebuilt 355. Lately it smells of gas after you shut it down and my friend said when he followed me to school today that he smelled gas strong while behind me. It also seems to build fuel in the exhaust cause when I let off the gas it shoots flames out and today I shut down and about 8 seconds afterwards it backfired. My gas cap seems to be bad because anytime I open it I get the good old hissing sound. My mom mentioned the gas smell and so did all my friends, I have a bad cold so I haven't noticed it that much. So how do I check if my choke is stuck open or how do I simply lean out the QJet? I have disconnected the choke previouslly and drove around and all it seemed to do was start slightly harder when cold.