Re: gearcase oil black and smells burned
My gear oil comes out like that almost every time I change it, which is once a year in the fall. That's what happens to it over time, and use.
I usually put about 100hrs on my engines per season and a lot of that is long, hours long runs out off shore. LU oil takes a lot abuse, heat changes it's color and smell.
I can't imagine why it hasn't been changed in 5 years, since it takes about 20 minutes to do, but I wouldn't try that again unless you like to buy new lower units.
5 years of abuse on the same oil is a lot for it. I'm surprised you don't have any water in it.
Change it, run it and then check it in 10 hours and see what it looks like.
As was mentioned go buy the fill and drain gaskets, and don't try to re-use them, thinking they are probably still good since they were just changed last year. They are one-time use ONLY, they are crush washers, when you tighten them they crush and they only crush once. So replace them everytime, might as well buy a bag of them, they are cheap.
Change it every Fall from now on if you want to keep it.
