Lower unit fluid

Drained lower unit on 86 25hp Evinrude, old came out milky so I know there was water in it. Left it in NY for the winter and always drain and refill. Never any problems. 96 40hp Yamaha? I have owned this 5 yrs and never changed the fluid cause it stayed in FL. Left that Boat/motor in NY this year. Old fluid was clean but Black. Filled with new lower unit fluid that I have used for years in Evinrudes and Mercuries. I will check it when I go up in the spring but Does Yamaha have their own brand of lower unit fluid?

They do have...if you do a google search it will come up or stop by a Yamaha dealer. Lower Unit » Yamaha Maintenance Matters

With that said any lower unit lube with the same spec will work. You definitely have water intrusion if it's milky. Could be one of the service screws did not seal right? But it usually is the shaft seal. I would pull the prop and make sure there is not fishing line wrapped up around the shaft,refill the unit,make sure the back of the screws and the surface they seal on are smooth and the gasket or washer they use is intact. Take it out for a few hours and test the oil again after words. If if the oil looks good then I would just keep using it and checking periodically. If after a few trips it all looks good....I would run with it but still check it occasionally.

There may be some other recurrent problem a Yamaha mechanic or someone with specific experience may know about



If you still get water going to have to have a new seal and the shaft will need checked to make sure it did not get bent on a prop strike. New seal won't last if shaft is bent.

Thanks for the quick reply. We have a Yamaha dealer here in town, I'll check with them. It is the old evinrude that was milky, has been for years. That is one of the reasons I drain it every year before we leave NY for Fl. Put a new prop on it 2 years ago. Runs great for an older motor, love the electric start and tiller steer makes for a perfect match to my 16 ft alum boat.