Sound like a air leak, it could be seals, torn intake boot . You might want to get it pressure tested. Steve

Casey: If your sure you have the Carb circuits clean then a air leak as advised would be a secondary issue that would produce your symptoms. A leak down test will validate this .

Note: A Rebuild Kit will not remove Residual Debris from within a carb . Only diligence , concentrated carb cleaner and compressed air will resolve this fundamental hurdle .