Stupid Person

I am posting this for my father in law. He has a 1994 Chevy 1500 with a newly rebuilt 350. The engine has around 2k miles on it. The issue is when he starts it, it wants to cut out unless you hold your foot on the gas. While holding down the gas pedal you can smell fuel while it's running.

New parts: Engine was rebuilt, new distributor, cap, rotor and fuel filter. The fuel pump is about two years old and the carburetor is the original with about 350k on it. I was thinking it was probably the carburetor but I want to get some advice from someone that knows more about this than me.

Thanks for any help.