Re: mariner 60hp 3 cylinder 1988
Those Merc 3 cyl, 50/60/70 hp carbs from 1976-1989/90 (?), the WM-6, -8, -9, -11, -13, -15, -16, -18 series are essentially interchangeable. Basically just some minor updates as time went by, like switch from cork to plastic floats, elimination of fuel intake screens, different jet sizes, stuff like that. And all of them use the same gasket kits, needles and floats, etc.
EDIT: Just make sure you're using the right jet sizes specified for your motor in the new carbs, might have to transplant those from the old.