you will most likely need to replace the carb float.

We did a tune up. The carb float was never adjusted but may be out of spec. The engine still runs rich with the air filter off.

Thanks for your info.

there are quite a number of things, any of which can make the engine run rich. have you done a correct and complete tune up? have you replaced the correctly adjusted the carb float when you had the carb rebuilt?
I think a new carb would be less expensive than tearing it out and apart more than about 4 times. and is it correct to assume the engine still runs rich with the air filter off?