1992 70 Horse Force lower unit oil change

[Ol daddy]

Force Lower Unit Lube Question

Is this the same in a 1992 70 horse Force? And also what was the end verdict? Push the new oil through the drain or pour it in the fill until it coes out the vent?

 

[GA_Boater]

Ol daddy Welcome aboard.

Moved your post out of an thread that has been inactive for years - https://forums.iboats.com/forum/engi...or-90-hp-force

New threads get more views and better answers.

 

[Ol daddy]

I want to change my gear oil in my 1992 70HP For e motor. I have heard mixed things from people I have talked to as far as if I need to push the new oil back up through the drain hole until it comes out the fill....or do I pour the oil in the fill until it leaks out the vent? Also which weight of gear oil is best for this motor

 

[Ol daddy]

Thank you sir

 

[kbh121956]

You remove the lower drain plug, you also remove the upper vent plug. You pump the new oil through the bottom drain until the fresh oil comes out the vent. Replace the vent screw (also a good time to replace the screws gaskets on both) Remove the pump from the bottom drain hole and replace the screw.

 

[Ol daddy]

This is true on a 1992 70 horse force?

 

[kbh121956]

Ol daddy, Yes. You pull the drain plug (screw) on the very bottom of the gear case. Do not remove the screw on the round part of the gear case, this is a pin that is part of your shifting. You also remove the top vent screw (there are 2 top screws). Allow the oil to drain. To refill, you fill the unit with a pump through the bottom drain until fresh oil starts to seep out the top vent. Replace the vent screw, Remove the hand oil pump and replace the drain screw. It is a good practice to replace the little round gaskets on both the drain and vent screws. If the old gear lube comes out milky looking (water mixed with lube) you have other problems. Any marine store and Walmart will have the hand pump and marine gear lube needed.

 

[kbh121956]

I use Quick Silver 80-90W premium gear oil. Here is a video on it. An older Force, smaller outboard but it's the same. https://youtu.be/afEBb6wID4M

 

[jerryjerry05]

The 92 70 hp uses the Mercury gear housing.
It has the simple drain on the bottom and a level plug on the top.
Just remove both screws and fill from the bottom.
And change the seals or flip them over at the very least.


BUT!!! if you have the drive with the 2 screws at the top??
It will say vent and fill.
You need to drain from the bottom and fill from the top.
I fill from the fill plug and then from the vent plug until it comes out both holes.
If you have this type?? there is a slotted screw on the side of the lower casing.
DO NOT REMOVE!!! it's a pivot pin and holds the shift linkage in place.