What viscosity gear lube do you all run 90w or 80/90w?

What non Mercruiser brand Amsoil, Mobil One, etc???

I believe the Service Manuals for Bravo drives say to use Mercruiser oil...only. I don't think this is just them essentially "selling their own stuff"; but rather simply the recommendation based on years of studies and millions of dollars of R&D. One can always find a detractor or supporter for any oil, or spark plug, or type of wax, etc. I have been on this forum a long time and have seen literally countless oil threads, whether that is engine oil or gear lube. And there is always anecdotal evidence from the fans or haters of any oil. There are tremendous forces at work on a marine engine outdrive gears...I simply go with the guys who make the things.

i second that... BUT !

8 years ago i was out of drive oil so took a chance with GM 75-90 synthetic gear oil and did not miss a beat ! I might have them refreshed for peace of mind ... but i dont run the boat hard at all so might help!

The Old Standard


New Extreme Performance from Merc Racing




Then for aftermarket many people like NEO and several Amsoil. Do some searches on those two here.

We use neo oil…after 30-40 hours still looks brand new. Likely won’t return to using merc

I used Lucas M8 synthetic gear oil and never had an issue. Like others mentioned there will always be opinions on everything out there from wax to oil to filters etc.

Go to wal-mart and buy the Quicksilver High Performance like SB posted. $10 a quart. Change it every season.

Just bought six quarts of Quicksilver High Performance 90W from Walmart. $10.47 a quart and they delivered it to my doorstep.

And a 5 quart jug or 3 of mobil 1 15w-50 ?