Haven't read all the replies yet but if this is a scenario where you have a little bit of camshaft and you only have 2 Corner idle as in primary, then there's a good chance you have the throttle blades open too far and the ported vacuum is now active.
If that were the case...you can lower the primary blades at the idle speed screw..then flip the carb over and you see a little flat head screw that adjusts the secondary throttle blades...open them just a hair more to compensate for the lowered primary idle speed... again if that's the case and there not some internal leak that's pushing fuel.
All assuming the timing is set right.