Engine flooding with gas - thoughts?

[brap999]

My c10 has been out of commission for 2.5 years. This past week I finally got around to putting it back together and started it up. It has a 350 with a holley 600cfm and a stock mechanical fuel pump. The intake flooded with fuel, which flooded the exhaust. It ran but wouldn’t idle. I pinched off the Rubber fuel line right before it connects to the carb and let the engine run just from the fuel in the bowls and it ran great until the bowls got empty. Am I correct in thinking there is crap preventing the needle valves from closing completely? I took the bowls off and removed the needles and cleaned everything, I can’t test it until the the new gaskets arrive though. If there is something else I should check I’d like to do it now while the carb is apart.