In addition to what everybody already suggested;

too much initial timing?
gas leaking into the carb from the floats too high?
a somewhat blown power valve? It can stretch and not be completely blown and it will let some gas into the engine at idle.

It could still be a vacuum leak. Some of those are hard to track down. If you put your hand somewhat over the primaries at idle and it runs up its getting too much air from somewhere it shouldn't. Otherwise, doing that should choke down the motor.


[addsig]