Hi guys

I recently replaced the carburetor on my 235 with a new one. The old one had broken and missing parts but was rigged to "sort of" run like that, and it was leaking out all the gaskets. With the new one, it starts much much easilier, and generally runs better, but still hesitates if the gas pedal is pressed down quick to "rev" the engine. Runs and drives just fine however.
I have played with the idle speed and mixture screws to get it to run it's best, but it still does this. So I'm now ruling out the carb as the problem. The plugs and wires were replaced too, and the points are clean. Any suggestions on what it could be? My thought is a faulty vaccuum advance on the distributer...sound feasible?