Make sure the carb spacer is in the right position.
It has a notch on one side. that feeds a little hole in the carb. If mounted in the wrong position your idle circuilt won`t work right at all.
This applyes not to all carbs, but it is worth a check.
Also make sure the throttle plate is almost closed at idle (one turn at the throttle screw - do the rest with the mixture screw). If the plate is open to wide, it overrides the idle circulit.
A vacuum gauge tells it all
Frank
