serious carb issues

well i took the carb apart today, blew air through all the passages and put it back together. Set the 4 corner idle screws each at 1.5 turns out and fired the car up...started right up!!! and adjusted from there! the car is running strong now, and doesnt stumble off the revs either, but i do have a slight vacuum leak however, and the lower the rpm at idle the worse it gets. It seems to be coming from the throttle shafts as they did have some play to them when i had the carb apart, and when the car is running if i push up on them to snug them the whistling goes away...whats the fix for this? new baseplate?