6lb pump blowing out carb?

What kind of fuel are you running? Ethanol 10%?
I can tell you from personnel experience that old school carburetors dont like alcohol.
If ethanol has destroyed the float needle and seat you are dead in the water.

Yes, the 10% crap ola… Some have said that running the ethanol treatment cuts down on the BS that sticks around and the collection of water. Have you heard of any of that?