I have never had a power valve to stick. They may have the diaphragm to crack, the spring to lose tension, or the gasket to seat incorrectly. This can cause gas to bypass it when the engine is not running and leak gas into the manifold. This will cause the engine to crank like it is flooded. Tapping on the carburetor will some times let the needle to reseat itself. A needle sticking wide open will cause the carb to flood out. A bad float that is leaking gas to go inside into the float will also cause the flooding. Find someone that really knows how to rebuild your carburetor, and save a bunch of money. The kits are not too expensive.
Thanks guys for your info and suggestions. I appreciate the info for both 2bbl and 4bbl applications...ALL of you guys clearly know your stuff and that's why I come here. I wasn't trying to start a sh*t fight over who knows more or anything like that...obviously people have different opinions and experiences and that's another reason I come here. I just hope we can keep it constructive because there's no good sense in being so hard on someone because of a difference of opinion. That being said....I'm going to check my float level today and checking my power valve.
I found some really good diagrams here for anyone interested in fuel passages, basic operation and information about the Autolite 2100. http://www.carburetor-parts.com/Motorcraft-2100_ep_422.html
