I have to agree with Carbguy on this one. I'll bet the throttle blades are open too far @idle, uncovering the transfer slots, and pulling fuel through the boosters. Try backing out idle speed screw until the boosters quit dripping, then readjust idle mix. You'll probably have to slow idle speed down after mix adjustment. I had the same problem a few years back and it ran me nuts! It turned out to be just that simple.....