Originally Posted by
Jim.Thompson
I suspected that and added some three bond sealant to the contact surfaces of the double thickness insulating spacer between the carb and the intake manifold. However, I am still not sure that the "O" ring inside the manifold which seals between the manifold and the intake port (or should do so), is doing to job. I will check that somehow.
Speaking of gaskets, have you checked your vacuum hole from the engine to te carb. Sometimes the gasket gets turned so the holes don't line up or, sealant gets in the hole and clogs it. No vacuum to the carb, equals no carb pump action, equals no sustained running. The engine may be starting on the prime and then quitting due to no fuel. Just an idea. Good luck.