Which gear lube?

[TillamookB2]

I have a late 50s Mercury Mark 55A. I have no idea what kind of gear lube to use. Some people say to never put fresh lube in from the top hole. Always pump it in thru the bottom hole and when it comes out the top to put the top screw in and then quickly put the bottom in. True?

 

[Brewman61]

Re: Which gear lube?

Yes, always fill from the bottom. When you're done pumping in the lube, put in the vent screw (the top one), then unhook your pump and quickly put that screw in.
If it was my motor, and I didn't have anything else to go on, I'd use a marine grade lube made for the purpose.
I'm betting any such lube would be far superior to what they used when that motor was new.

 

[gss036]

Re: Which gear lube?

I would but a qt of synthetic Pennzoil gear oil and a pump. That way you have enough for probably 3 changes, maybe more.

 

[robert graham]

Re: Which gear lube?

Any Marine Outboard Gear Lube should work fine, Walmart carries several brands, including their own. Pump it in from the bottom. Good Luck!