I have a 50 hp merc ser no 5267736, should be a 77 I believe. I need to find the plastic inlets that the fuel line hooks to on the carbs, I broke mine off by accident.
My engine isnt a 500, it says 50 on it. But other than that, it looks the same. 4 cyl, 2 carb, integral fuel pumps. Time you add shipping, it has min order of 30 bucks it looks like for the part.