Lower Unit Oil

[Pete Collin]

Hello All,

 

I am getting my boat ready for the season.  The local NAPA only had small tubes of lower unit oil.  Too small for my two motors.  On the same shelf are good sized jugs of oil that is also 80W90 oil, but not labelled for marine use.  Are all oils of the same weight and thickness identical?  The guys at the store couldn't tell me.

[ERABBIT]

Pete it should be changed or at least drained in the fall. Lowerunit oil should be the same but I wouldn't do it. JMHO.

[Frogger]

Yikes, yea Ed is spot on. Hopefully there's no moisture or water in the oil now as it sat during the winter. Or maybe it's in heated storage which is very nice. But if not, water freezes causing lower unit to go by by. You'll want to change it in the fall before it freezes.

Sent from my iPhone using Lake Ontario United

[fisherman 57]

I use 75-90 synthetic lower unit oil

[Pete Collin]

I drained it last fall, am refilling it now.  Thanks for the tips.

[Frogger]

Good deal, sorry forgot about the question, I use the 80/90 on my envirudes.

Sent from my iPad using Lake Ontario United

[rolmops]

The oil is usually the same if the numbers are the same. The only difference is the grade for engines with electronic shifting (Johnson/Evinrude 1968 to 1971).

You can just go to Walmart and buy their home brand lower unit oil (made by Pennzoil).

It is not a good idea to leave the lower unit empty all winter. Think of it as a gearbox,you do not want rust to start forming on your gears. Also,you must replace the small hard washer seals because they are only one time use.

[lineman49]

Tractor supply has their brand of gear oil & it states on the bottle that it is marine grade & also what brands of motors it meets or exceeds their requirements. Much cheaper than boat motor manufactures price.

[MCF]

I purchased a 5 gal container of 80/90 oil from the local Pennzoil distributor(who was big into boating at the time) a long time ago,  just about getting to the end of that container, have used it in various outboard and I/o lower units over the years, no issues.  Now that synthetic has become available, I just that in my four stroke outboard.