Do I need a carb?

[TheShadow619]

I have a Merc 165. Carb tag number is 7040080. Throttle pump hasn't worked right in years. Kitted it last year. Still doesn't work right. It won't hold fuel. If I hit the throttle once, no fuel shoots from the pump, but If I pump the throttle a few times it will shoot fuel from the pump. I'm guessing the inside of the carb is worn to the point it won't hold fuel in the pump house. Unless someone has any other suggestions, Please. Carbs are expensive.

Other question is, what is the difference in tag numbers 7040080, 7040083, 7042183, 7043183, 17059050? They are all for Merc 165 and all look the same too. Can I interchange them?

 

[airshot]

Either a leaking gasket, or a gasket installed incorrectly, or you could have a pin hole leak in the casting itself. I would bet on a bad or incorrectly installed gasket.
I will let someone with more knowledge comment on interchangeing the carb numbers.