And i have tried everything to pull carbs and 3&4 apart I need to see if there is any other issues with these two carbs because so far i have had to replace the hold screw for the enrichment valve... the other screw I caught in time to screw it down tight. After I got the Carbs back I had to tighten the diaphragm screws but all i have to say is WOW $600.00 later I never thought I would be going thru the carbs myself and finding plugs put in the wrong holes upside down and one gasket pinched on the carb bowl.... the needle valve screw yep only thing holding the jet block in...