Before we can aswer that, we need to know some stuff. Which engine are you running? Which Carburetor do you have?
I have a Carter W-1 on a Chevy 216. On the back side of my carburetor there is a screw with a spring that you turn to mess with the mixture. This information may or may not be what you're looking for. If you've got a 50's era carb, you may have a Carter Y-F or a Rodchester, and neither of those, AFAIK, are the same set up.
Lots of people have electric fuel pumps, so I doubt that this is the issue. If the Carb were clogged up you'd have overflow, but that's the same with any fuel pump.
Welcome aboard, BTW! We can probably get you straightened out without too much trouble.
