I just went through a similar situation with my Rochester B. I chased everything from vacuum leaks and fuel delivery, to spark and timing. Everything checked out. It would start but not idle.
If your Rochester is older, I guarantee there is gunk in there that shouldn't be. Get a rebuild kit. My power piston was completely stuck, and if you're new to these carbs (I was), you would never know the power piston is supposed to move up and down. When the power piston seizes it almost looks like it's pressed in the body of the carb. It should move freely and squirt fuel into the main body. You can hear it working correctly. Aside from the power piston there could also be several other passages gunked up. I soaked mine and cleaned thoroughly with carb cleaner. Also pay attention to the "check balls". If you take apart one of these carbs you won't even notice them fall out. There is a ton of good information on this site, and Mike's Carburetor can help with a rebuild kit.
Also, I can't speak for other people's rigs, but my truck almost always needs a quick choke to start. Even when warm. Otherwise it will crank and crank.
Last edited by FRanch53; 03/07/2023 10:38 PM.
