Replacing the Seals in a 1980 Mercury 50HP

Can anybody out there give me the basic steps for replacing the lower unit seals in my 1980 Merc 50. I have the prop off, the little slide collar washer under the prop, and have broke out the plastic screw ring that threads into the inside of the prop housing. At this point I don’t know what comes next. It looks like the piece that sits around the prop shaft and the seal could have a pin at the bottom of the threaded area inside the housing but it doesn’t seem like something that can be pulled/pushed out. Any help would be appreciated because at this point I thinking that I’m head into a marine shop for something that I started out thinking I could do myself.

Usually the larger public libraries have the service manuals for them. Whenever I need to do something, that’s the first place I go. If it looks like I can do it myself, it’s always better to double-check; sometimes the manual calls for tolerances and required tools that I just don’t want to deal with.

Good idea, I had forgotten about the library.

Hey bud, ever get those seals replaced in the 50 horse. I seen this old post and i work on boatmotors. I’ve got an old 59 merc 4 cylinder that runs like a rocket. Just wondering if you have,Later… mossydan

I ended up taking in because it got to be more work than I was looking for. It ended up being a good thing because he replaced the seals and pressure tested it and it still had a leak around the top vent screw. The ended up doing a little sanding in order to get the screw to seal properly. I had to fork over a lot more money than I wanted to though.

Troy if that vent screw ever leaks again or you think it does go get a fibre gasket and use that to seal the fit, it will last for a few years and thier cheap to replace. Ive got fibre seals on all of my screws and they’ve never come out.

Thanks for the tip Dan.