You mean so it will NOT take off. Basically you are kicking in the clutch within the transmission. There is a screw on the front of the carb, this is the idle screw (there is a picture in the manual). Turn this about 1/4 turn counter clockwise. You can also turn the low speed needle about 2 hours (look at the face of a clock) counter clockwise as well to lower the idle, but this could cause hesitation if you are too rich on top.