I used Mobile One in my Kaamas, with nary a problem.

I have a 1992 Bravo one. I have not been nice to it. It's never needed any work. It had a 454 mag driving it. For the last 4 years it has a 496 HO on it. I have never used anything but the Mercrusier green HP outdrive lube. I'd say 16 years is a pretty good statement as to the quality of the Mercrusier stuff.