Hello.

I had a tiny bit of water in my B3 and after a few days of sitting on land I noticed a leak at what appears to be the top cap. I have the O ring. Any tips? Perfect seal? I'll pressure test at some point, but I need to run the boat this weekend and I figure swapping out this O ring is better than doing nothing.

From the looks of it, you will probably have some corrosion at the mating surfaces. There's a few O rings under the top cap https://www.mercruiserparts.com/bam/...y/30971/952/70

I hope not. I have the main one part 16.

But ya know what? Looking at that diagram again it looks like maybe the shift shaft o ring is more likely, given the location of the leak. Maybe I'll save this for a better time when I can really get in there. I have the "O ring" for the rear cover too. Maybe I should just do it all at once. I'll fill the drive with fresh oil (that apparently is made out of liquid platinum now) and run it for the weekend. Next week I plan to pull the drive for reasons anyway. I just didn't get to that point and it's time to open up my island camp.

I think corrosion is not very likely on this drive. The PO was very diligent about keeping it painted. The bearing carrier behind the props looks perfect, and that seems to be where the cancer starts on these from what I've seen. Maybe I'm lying to myself but that's my hope.

Quicksilver hiperformance gear oil is $10-$11 quart at wally world.
https://www.walmart.com/ip/Quicksilv...E&gclsrc=aw.ds

Stop paying platinum prices

And yes, i see lots of corrosion in that pic too. Most likely anode issues. I have friends that paint instead of replacing anodes. I stopped arguing about it with them. My okd drives look close to new. Same with customers i service. Never been repainted. Theirs repainted many times and still bubbling/bare soots/etc.

I found out that 8 in stock at Walmart really means zero. So I had to go to the boat shop (which I prefer most times) where it was $21/quart.

I'm still hopeful on the drive. This guy was super anal. Did anodes and paint every year. I'll know more when I open it but here is under the prop.