Broken plastic barb on 90 Hp Merc Tower of Power Carb

[finn92]

Hey guys,

I rebuilt and was installing the carbs on my 80s tower of power 90 hp merc. I ended up snapping the black barb fitting on the carb housing that is fed by the float bowl. I was wondering if anyone knew a fitting available to click onto that existing metal flare. I cant find them on the exploded view of the MWK-39 carburetor.

Thanks

Finn

 

[jimmbo]

That was part of the 'Back Drag' feature of the carb, designed and added to the carb in 1975. it reduced the atmospheric air pressure in the fuel bowl under high rpm low load conditons thus reducing the amount of fuel entering the carb venturi and improving gas mileage. Worked great for a while until alcohol started being added to gasoline, which resulted in the air fuel mix being too lean and pistons started melting. Mercury recommends disabling the feature by plugging the hose with a ball bearing, in your case plug the hole with something that won't fall out, epoxy putty comes to mind, and plug the hoses on the two remaining carbs

 

[finn92]

Thanks jimmbo much appreciated