What gear oil can i use in my 83 Johnson 15hp gear case? Can i use 75-90w synthetic gear oil for cars? or do i have to go buy something special. And how much do i put in? Why can't i put oil in from the top screw?
What gear oil can i use in my 83 Johnson 15hp gear case? Can i use 75-90w synthetic gear oil for cars? or do i have to go buy something special. And how much do i put in?
Use a marine-grade oil designed for lower units. I don't know the capacity for your motor but it's not so much that you should try to avoid using what the manufacturer recommends. Probably around a quart.
BRP Hi Vis is listed but Marine Synthetic 75-90 gear oil is fine. Gearcase capacity is 9 ounces.
The motor should be in the running position when filled and filled from the bottom (fill) hole until the fluid runs out the top (vent) hole. This eliminates the air pockets and also prevents over-filling which can blow out the seals when the gearcase heats up while running.