wrote
I thought gasket seal was always needed when
replacing gaskets on anything. Yea, or nay.

My Mercruiser service manual doesn't call for any sealer on the water pump
gaskets. I've never used any, and one good reason not to is that I replace
my impeller fairly regularly and it's nice not to have the gaskets stuck and
going to pieces when I pull the housing off. I don't think you need a
perfect seal (tm) on the water pump gaskets because all you'd be doing is
keeping water from getting into water. Obviously you don't want massive
leaks because you want the pumped water to go where it's supposed to, but a
little seepage out of the pump is just going to go into the surrounding
water there in the exhaust passage. The water pump base has an o-ring around
its outside diameter where it plugs into the gear housing and a seal where
the shaft goes through, and those are the things that keep the water and
gear lube apart. The one place the manual does call for sealer is the metal
insert that goes into the pump housing, the thing the impeller rides in,
presumably to help keep it from knocking it's little tab off and going for a
spin.

All this applies to my Type-1 drive with its plastic pump body and oil seal
in the base. Yours may be different.