You can check for an intake leak using a propane torch. You just move the unlit torch along the intake, and if the propane gets sucked in, you'll hear a difference in the engine. By checking the carb, do you mean you took it off the engine, and opened it up? Often there is sediment or other junk in there that can clog up the works. A "kit" for the Rochester B carb is cheap. Just follow along in the shop manual when you rebuild it, and make sure you put the little balls back where they should be, and set the float level to where it should be. You may, or may not have a fuel filter inside your B carb. Just keep at it!
