Lower unit lube?

[BobT]

Is there any reason that we can't use regular 80-90 gear oil for outboard lower units? Considering the massive heat sink they have (lake) I doubt heat buildup is a problem. About the only reason I can imagine is possible compatability issues with seals.

Bob

[jwhjr]

I use the Fleet Farm brand of 80-90 for my lower unit. It lists on the back that it can be used for them. I do have an older motor though ('81 Evinrude 35 hp). If I had a newer one I'd probably go with some higher quality oil.

[Capt. Don*]

It depends what weight it specifies, if it calls for 80W-90W go ahead and use it, just make sure you have no water leaks. Newer high horsepower engines call for synthetic, synthetic blends or different weights for good reasons. The pressure on the face of the pinion gear and shaft gears under heavy load can be tremendous, lube weight and quality can make a difference.

[theoilman]

Check out the AMSOIL Synthetic Marine Gear Lube: 75W/80W-90, full synthetic, and the only one I have ever heard of that will tolerate 10% water without losing lubrication or protection.

[BobT]

So, marine gear oil is formulated to handle more water contamination than automotive gear oil? Never thought of that but it definitely seems logical.

Bob

[Cliff Wagenbach]

 Originally Posted By: theoilman

Check out the AMSOIL Synthetic Marine Gear Lube: 75W/80W-90, full synthetic, and the only one I have ever heard of that will tolerate 10% water without losing lubrication or protection.

I started uning Amsoil gear lube in my 115 Yamaha a couple of years ago and it has worked out great!

Cliff

[idratherbefishing]

I didn't get a chance to change my lower unit oil last fall, so i did it this afternoon and when i took out the bolt a little water squirted out first before the oil flowed out. The oil didn't look milky. Is this normal? Should I have the seals checked? It is a 2002 Yamaha 60 4stroke.

[Valv]

 Originally Posted By: idratherbefishing

I didn't get a chance to change my lower unit oil last fall, so i did it this afternoon and when i took out the bolt a little water squirted out first before the oil flowed out. The oil didn't look milky. Is this normal? Should I have the seals checked? It is a 2002 Yamaha 60 4stroke.

I would have it checked, you might have seals problems.

Water will separate from oil if left standing for a long time, naturally being heavier will drain first then oil will follow, that's why you didn't see it milky.

[jwhjr]

Depending on the amount of water, I'd possibly be concerned about it having frozen over the winter. I always change it in the fall for this reason. As Valv stated I'd have the seals checked.

[idratherbefishing]

Thanks for the response, I talked to my mechanic and he said to use it a little and then change to oil again and check if there is water in the oil, so that is what i am going to do.