Hello. Thank you for providing winterizing tips for my 70 h.p. 1979 Chrysler outboard. It's a good thing I have decided to change the gearcase oil myself this time because I found out there was no oil, just stinky water draining out from my gearcase when I went to change the oil !!! Is it a seal that needs to be replaced, what kind of seal is this and can this be done by myself or do I need a boat mechanic? Thank you.