Gear Oil on 85HP Force

[Horse4190]

How often we need to change the Gear Oil - is it yearly or never (just adding on it)? This is for my 85HP Force Outboard 1989 Model.
If I need to change/add the gear oil, do I have to use the recommended EP90 outboard gear oil from the instruction manual or SAE80W-90 will do? The Marina also suggested to use the mercury and I am not sure if this is acceptable? Thanks again for your help.

 

[Scott Danforth]

you change yearly, that way you can check for water intrusion, etc.

you also grease the prop splines yearly

merc High Performance gear lube is fine.

 

[roscoe]

Drain and fill once a year.
Usually before putting it away for the "winter".
Definitely before freezing weather if you live where it gets cold.
Inspect old lube for metal shavings, and for water !!

Water in the lube will freeze, and crack the gearcase.

If you find water, you have an issue.
Water can get in through several places.
Waterpump, driveshaft seal, shift rod seal, prop shaft seal, and the gaskets on the drain and fill screws.

Use a marine grade gear lube. Mercury, Quicksilver, or generic, as long as it is marine grade.

not sae80/90

 

[jerryjerry05]

As long as it's 80-90 any gear oil will work.
But the Mercury oils will work better.
I check my oil after each trip.
You never know when the "new" seal kit will start to leak.

Since you have a lower unit that used a set screw for a drain seal, they seem to weep a little bit of water.
Use a commercial grade thread sealer after the threads have been cleaned of any oil.

 

[Horse4190]

Many thanks for all your help. One thing to know, the Shift Pivot Screw NEVER to remove when changing the gear oil on a 85HP Force Outboard. I am thinking to just put a silicon sorrounding it of the shift pivot screw to prevent from removing it and the water to come in. Not sure if this is a great idea??

 

[roscoe]

Sure, anything to keep you from making that mistake.
A dab of silicone will keep you from putting a driver in there, but would be easily removed if you ever needed to.

 

[jerryjerry05]

That silicone won't hurt a thing.

In all the years I've worked on these motors, I've never seen one leak at the pivot screw.

 

[Horse4190]

Many thanks. Yes I learnt from my mistakes. You guys are awesome!