How do I add gear oil to multiple fill plugs on OMC stern drive.

[Serf27]

Hey everyone.
I have a 1984 OMC Stern Drive.
Just about ready to add some oil to the drive.
I see a drain plug and fill plug on the lower gear case, I see 2 fill plugs on the upper gear case and a fill plug on the intermediate housing.
My question is, do all of these fill plugs take the same oil? Or what oil goes in each one?
Preferably something I can find at an auto parts store or Walmart.

Only thing I know or at least I think I know and maybe it’s right, on the gear case, start filling from the lowest fill hole and slowly work my way up?



Here are some photos of the parts diagram showing the fill plugs.
Plug 47 and 41
Plug 2 and 16
Plug 83.

 

[southkogs]

Lower unit, upper unit and the intermediate housing are all separate gear cases. They all take regular 90wt gearcase lube (nothing special), but they each fill independently. Lower unit will have a fill hole on the bottom, and a breather hole up above. Upper unit has a fill hole on the side, and the breather is on the very top. The intermediate is a single hole access.

 

[kenny nunez]

You may have a drain and a fill on the intermediate, I believe 78 and up 800-400 models have the drain on the intermediate.
As Southkogs said the same oil in the entire drive platform.
There are Zerk fittings under the rubber bumpers where the drive mounts, inside the hole on the forward section of the exhaust housing and another where the steering shaft comes through the intermediate.

 

[Serf27]

Thanks to both of you. I’m not sure what is meant by breather hole. Is that the fill plug?
Do I add oil to each fill hole until oil comes out of the hole? The upper gearcase bolt at the very top is long, almost like it’s a level checker. And does it matter if the drive it tilted up? Or should it be all the way down.
I did find the drain plug on the intermediate.
I see the zerk fittings behind the bumpers I need to look for the others, I just add grease to those?
Here’s some photos of the actual drive.

 

[CaptnKingfisher]

My experience is mainly with outboards but someone can correct me if I'm wrong. Tilt engine to full down position. Open top and bottom plugs on each section to drain, fill from bottom plug (I use a hand pump that attaches to the fresh oil container) and pump oil into the housing until you see fresh oil coming out the top plug. Then plug the bottom, plug the top, move onto the next.

 

[Bondo]

My experience is mainly with outboards but someone can correct me if I'm wrong. Tilt engine to full down position. Open top and bottom plugs on each section to drain, fill from bottom plug (I use a hand pump that attaches to the fresh oil container) and pump oil into the housing until you see fresh oil coming out the top plug. Then plug the bottom, plug the top, move onto the next.

Ayuh,...... I agree with this, Except,.....
I put the top vent plug back in 1st, 'n you'll loose less oil when ya do the bottom plug, due to the vacuum created,....
Just like yer finger on a full straw,....

 

[southkogs]

^^ Yup.

And on the Stringer that top plug on the upper gear case is a dipstick (of sorts). I would fill from the bottom of the gear case, and watch for lube at the top to come out. Drive should be tilted as "down" as you can get it.

Just add grease to those zerks: and look for one at the front of the drive (right around where it pivots). That greases your pivot, but also helps with exhaust gasses.

 

[Serf27]

I did the fill procedure on all 3 last year. Since then it’s had about 1.5 hours of run time on land and in water.
Some may have seen my latest thread where the lower gear case blew up.
I checked the oil in the upper gear case and intermediate housing.
Inner mediate housing looked the same as last year when it was new and went in.
Upper case oil looked milky.

Why do you think it was milky?
Bad o rings on the fill/drain plugs?

I ask because I may get a used lower case but it is pricey.
If the upper case needs extensive work then getting a new lower may not be worth it.

Thanks.

 

[Scott Danforth]

pull the drive, split the case.

you most likely have a failed water pump. especially if it was packed with mud and water, it may have froze over winter.

other potential sources are a bad ball gear seal.

 

[Serf27]

A new water pump kit was installed last year and water drained from the engine.

I see 2 back to back seals for the ball gear,
An o ring for the exhaust cover, and o ring for the exhaust and an o ring for the top cover that may be possible culprits.
Parts number 21, 27, 38, and 57.