This is my second 2 stroke 5o cc china engine, mounted it on a mountain bike. I got it running, but then came the carb problems. It started to leak gas through the carb filter all over the bike. Took carb apart to see if anything was out of place. Put back on and the problem kinda went away. The engine starts but throttle grip wont move. I can throttle up the bike using the choke lever.. WTH!! I played with the "C" clip.. moved it up one notch, tried one down from factory.. nope still having the problem, then moved it back to factory setting. I have had the gas blow out the head gasket and muffler. Basically I start the bike with the choke level in the upward position, but when I go to lower the choke lever the bike engine speeds up, and if I put the choke lever all the way down it cuts out. The choke lever is acting like the throttle.. WTH Should I get/replace carb with new one or upgraded one, this carb seems to be cheaply made. I've had nothing but problems with this engine, including the shipping woes.. I'd thought I try to fix this carb problem first and see if this kit is worth keeping. I've read that these china girls always need tweaking. I don't want to tweak .... I want an engine that's suppose to work . I got better things to do than to "F" with an engine/carb all the time. I don't want to buy a 500 engine, but I also don't want pos. A nice simple engine than runs constantly with out much maintenance. Any suggestions on this? P.S. Do I need to turn off the petcock when I turn off the engine?