I'm not sure what the final cause was, but this is what I did. I adjusted the float hight on all the carbs according to Clymer and still had the problem. I took the bowls off again and notices that the float hight on #3 was not where I had adjust it. I swapped the #3 and #4 needle valves thinking that if the problem is the needle valve then # 4 should leak. I readjusted the hight on #3, thinking maybe it was stuck a little the first time I adjusted the hight. And reassembled every thing again. #4 started leaking, I rapped on the bowl a couple of times with the handle of a screwdriver and it stopped leaking. I'll keep an eye on it. Aren't gremlins fun.