slowgoer,
A standard idle adjustment on these carburetors is 1 1/2 turn out. I don't think this would be a concern above a idle.
Your problem sounds almost like a power valve issue.
Typically, there is a phenolic spacer under the carburetor. The gasket between the spacer and the carburetor base has small slots that have to line up to a port in the carburetor base. This allows the carburetor to sense vacuum and signal the power valve to operate.
If you DO have this port exposed, and the setup isn't working, this along with the malfunctioning vacuum port leads one to think the rebuild might have been botched!
Could this be the case? Was the rebuilder a competent carburetor man or experienced mechanic.
The timing could be a problem too, but this would be secondary to getting the vacuum advance to operate as it should. Keep looking!
Stuart
