Where do you have the idle (pilot) mixture screw set to? It should be around 2 1/2 turns out. Adjusting the idle speed screw in opens the throttle plate a bit and reduces the affect of the idle mixture circuit. In that case, the carb is trying to operate on the main jet and needle circuit. The fuel from the idle circuit enters the air stream through a few tiny holes in the throttle bore right at the bottom of the closed throttle plate. My guess is that you still have a restriction in the idle circuit....pilot jet, idle mixture screw, or the fuel passages.

Ride on
Brewster