For Cobra guys who have water in the gear oil….

One of the main causes of this is the water pump seal in the water pump adapter which is what the impeller housing bolts onto. There is a you tube video by Micheal Roemer that explains an easier way to do this than what’s in the shop manual. To change that seal the water pump adapter has to come off. The way OMC describes to do in in their shop manual doesn’t cut it. The way shown in the vid involves tapping 3-3/8ths holes in the 3 holes in the adapter for the water pump bolts. Then you thread in 3 3/8ths grade 8 bolts & use those to push off the old water pump adapter. This works great I had it off in about a half hr. There’s an OMC repair/parts place up in Canada that sells an improved water pump adapter with a double seal to keep water out. I got this part from then and installed it, fit nicely. Next going to do a pressure/vacuum test to make sure I don’t have any other leaks. Funny thing is that last year it passed both tests this year there was a lot of water in the gear oil.
This is the place, if you want one of the adapters with the improved double seal you can call them & they will make one up for you. This helps with sealing because often there is a slight ridge worn in the water pump shaft and the original seal doesn’t last that long. Google Wayne Coll you tube he also has a good vid on this and explains it well….

Where did you order this part from ?

www.sterndrive.info
AKA TC Electronics and Marine in Ontario, Canada

also forgot to mention, the water pump adapter has 2 o rings on it, a large one on its circumference and a smaller one on the back side that seals around where the water pump shaft bearing is. That smaller one on mine was totally deteriorated, and certainly could have been a source of the leak.
I followed the instructions in the OMC shop manual coating both o rings with OMC gasket sealer, as well as the gasket for the adapter on both sides. My experience with this stuff in salt water is it is very good for keeping water out of threads avoiding having bolts seize up.

scroll down to the bottom of that page, it's the last item on the page.
they make them up for you so there is a bit of a lead time.