I am rebuilding a 2bbl merc carb. My Clymer and the diagram that came with the gasket kit show a screen, check-ball and retainer clip at the bottom of the accelerator well. When I took the carb apart I did not find these items. I bought the boat used, so I don't know it they have been removed or if they are not part of this carb. The carb was flooding after being run hard. It started up alright, accelerated without any missing. Is it possible that my carb just doesn't have these parts?