Will the throttle close correctly with the throttle and transmission cables disconnected from the carb? Is the choke releasing completely and the fast idle cam dropping out of the way? With the choke fully open, crack the throttle open ~3° and wiggle the throttle shaft fore and aft. If there is greater than ~1/64" of side-to-side play in the shaft, the shaft bore is worn out and the throttle plates are not centered, causing them to hang up on one edge. The solution is to rebush the throttle shaft bore. If there is 1/64" or less of radial play and the throttle plates are hanging in their bores, you can try recentering the plates.