carburetor vent hole question

I recently rebuilt my zenith carburetor on my 1977 lowrider. Everthing went fine with the rebuild kit, no problems. However there is a small vent hole on the body of the carburetor, just above the bowl, right by the throttle linkage. I keep getting gas leaking out of that vent. Its a small amount but still, it should be leaking out and it wasn't doing it before.

I set the float with a 3/16" drill as directed. So I don't think that is the problem. I've taken the carb apart a few times to see if I missed something. Not sure what to do? Is this vent suppossed to be plugged with something?

When the fuel leaks out of the "vent", does it also flow out of the overflow drain tube? If not, it sounds like something is missing. On many carb bodies I've looked at, there seems to be a small ball bearing plugging the hole you are speaking of. Is there one in there? If not, that's probably the culprit.