I am working on a 1981 C10 pickup 350. I have spark, checked firing order, checked the float, needles, and seats in the carb. But it keeps flooding out and backfiring. And now it won't start at all but it will turn over.

 

You say that you checked the float and needle. Does that mean you adjusted the float height and also checked to see if the float is sticking and not shutting off the gas?

 

oldchevy, thank you for responding. Yes, I adjusted the float height, etc. Everything in the carb is working correctly. The carb itself was replaced 1.5 years ago. I have replaced plugs and wires and checked all of the other obvious causes with the exception of compression which I will check tomorrow.