Problem occurs when engine is cold. The engine will start and tend to stay lit when throttling back to idle. However for about the 1st minute or two advancing the throttle will tend to kill the engine, unless I quickly bring it back to idle. After about two minutes of operation everything is fine...no problem. My Air/Fuel gauge reads very lean when throttle is advanced at first (when first started and cold). Within two minutes the A/F goes rich (10.5) until the engine temp goes to about 110F and then the A/F goes to 14.7...where it should be.