I normally change the bottom end oil each fall, at the conclusion of the season. The boat didn't get a lot of use last year so i didn't bother changing the bottom end oil. I drained it this fall and the first thing that came out was maybe half a thimble full of clear water. If i hadn't of been watching i doubt i would have noticed it. After that it was oil, with no discolouration as i use synthetic and it will not mix. I use Royal Purple, and have been for years now.
My thought is to run it next season and keep an eye on it. Does that sound like a reasonable thought process?
Thanks