for my enlightenment, what kind of carb is this and what kind of motor is it. Most 2-cycle kart engines won’t idle. And if you set the carb to idle, more than likely you’re running too rich to run on the track. Way back, I did use a piece of a match book cover under the butterfly stop to keep the plate partially open and the engine idling. On the first blip of the throttle, the match book cover was gone.