Rick L., your symptoms are of governor problems, not carburetor.
Set the governor shaft in the arm per the book. That is, loosen the clamp on the shaft, pull the arm all the way forward so that the throttle plate is wide open, turn the governor shaft counterclockwise until it touches the stop, then retighten the clamp. If the shaft shifts in the arm at all, you will lose governor control.
Spec idle speed is 1000 RPM. This adjustment is the throttle stop on the carb. Set the throttle control bowden wire so that it is just pulling the throttle off the stop at minimum on the lever.
The spring needs to be clean and in good condition. It goes into the third hold up on the governor arm for the initial adjustment. I have mine in the second hole on the throttle arm (the arm connected to the bowden wire).
A quick check for proper governor action: with the engine running at about 2000-2500 RPM, push forward on the throttle linkage lightly with your finger. If you do not feel firm resistance, and the arm will go all the way forward, you've got governor problems inside. If it moves a little, then stops well before full throttle, the shaft has slipped in the arm.
If you can't get good clamping, score the governor shaft lightly to make a few ridges along it, check the condition of the arm clamping surface, and use a 1/4-28 fine-thread bolt in the clamp arm.
Hank