@Phreakish yes the kd cable goes slack at the carb. Ive tried numerous springs, and always have had 2 springs on it. I even cut the springs to be a touch shorter hoping that would help.
That's odd. The only other thing I could suggest is to check the torque of the carb base nuts. It's not hard to warp a carburetor base by over-tightening. When warped, it can cause a bind on the throttle shaft sometimes.