66 Merc 50 Gear Lube Question

[Alumarine]

Hi there. Just picked up a 66 (I think) Merc 50 4cyl Serial no. 2096957 and have a question about lubing the gear case.

I was going to put 90W marine gear oil in but it looks like there is grease in there? Is that right? If oil is best, what's the capacity?

Also, just above and to the right of the vent plug is a larger plug which I think is the Gear Housing Flushing Hole. What is that for?

Thanks for any help.

 

[Laddies]

Re: 66 Merc 50 Gear Lube Question

Your engine is a 66 but it should have 90# oil in the unit, some people put grease in them when seals start to leak

 

[Alumarine]

Re: 66 Merc 50 Gear Lube Question

Laddies, thanks for the info. 90 Weight it is.