Timmy:
I have heard those carbs are sensitive to fuel pressure, don't like more than 3 or 4 psi. When you shut the engine off, look down the throat and see if gas is dripping from the fuel nozzles. If so, then look at too much fuel pressure or a leaky needle and seat or too high a float level. If you see no gas dripping, then it still must be a leaky power valve. The gasket may still be leaking, or the diaphragm could be damaged. Has the engine backfired? That can rupture the diaphragm.
John
John - "The Hoosier Hurricane"
