Turn that mixture screw until you wear the threads out- - - -it doesn't change a thing except the idle mixture. Your "rebuilder" shouldn't be working on anything more complex than a hand-cranked can opener if he can't make a Rochester B run at least reasonably well. Even at its best, a Rochester can't hold a candle for a Carter carb to go by!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!