Trying to get my 2001 500cc scrambler figured out. It is leaking fuel out of the overflow, will not idle with out pressure on the throttle, and is back firing. When I shut the fuel off it will idle down and will run if I turn up the idle. I have pulled the carb off twice now and checked everything out and cleaned it. Everything looks fine. The float looks good and seems to be working properly. What am I missing?