1969 OMC Outdrive Oil Change help please

[BudL1te]

I have a 1969 Crestliner Tri-Hull with an OMC outdrive. The motor was Gray and roughly the same a the mercruiser 120 I put in it. (Chevy II engine I believe)

This is an electric Shift drive.

I have a plug on the bottom left, a plug midway (or a little more) on the right hand side, A plug (Large Flathead) at the top (no dip stick) and a large plug about midway at the back that feels plastic and is raised (Not flush like the other plugs.) I took the lower plug out and oil came out, I tool the plug from the right upper and oil came out.

I am confused now. I haven't see any similar to mine in the threads or you tube.

What is the best way to change this oil???

I tried to blow air in the lower plug and it did not appear to push anything through the right hand plug as I was expecting so I am stopped here.

Any Ideas?

 

[southkogs]

Not sure I'm following which holes you're talking about. Got any photos?

Generally the way to get the oil out is to pump it out through the dipstick tube.

 

[BudL1te]

No Title

Looking at the pic, I think I am draining oil from two places, I don't know

 

[BudL1te]

Sorry, I mentioned the engine only as a reference as I do not know what exact model I have. I do believe OMC but not sure of anything else other than that.

 

[BudL1te]

1969 OMC Inboard Electric Shift not going into reverse.

Was working great then it wasn't

I don't have a manual or know a lot about this drive.

It will go forward but putting it in reverse the motor just revs but no movement.

Any Ideas on where to start looking/tracing?

 

[southkogs]

Oooooohhh - we're talking gear lube. Okay: two different chambers. Upper gear case, and lower gear case.

Lower gear case = flat head screw on the bottom (drain and fill port), flat head screw on the port side just above the anti-cavitation plate is the vent. You'll need a pump (See HERE) to pump the lube into the lower. Use Type C gear lube ONLY.

Upper gear case = Flat head screw on very top cap is vent port, and you can top it off there if you need to. Turn the stern drive all the way to the left (port) side and you'll see a flat head screw on the starboard side almost parallel with the pivot caps. That's the drain (messy as all get out) and fill.

 

[southkogs]

If it's a 1969 120, then you should be right about the Chevy II. Inside the boat on the engine, there should be a tag (maybe on the rear motor mount, typically on the starboard side) that has a number on it. Should read something like "CUFM-69B." That number will identify certainly what you have.

You're in an electric shift which is an old (read that antiquated and obsolete) platform, and OMC has been outta' business since the 90s. You can keep them running, but it's not always easy.

Do you know you have Type C gear lube in the lower?

 

[BudL1te]

No Title

I don't know what was added, I took it to a shop when I got it and they replaced the water pump/impeller and did the oil, I just wanted to do a fresh change.

"Lower gear case = flat head screw on the bottom (drain and fill port), flat head screw on the port side just above the anti-cavitation plate is the vent. You'll need a pump (See HERE) to pump the lube into the lower. Use Type C gear lube ONLY."

There is only one screw on port side

Upper gear case = Flat head screw on very top cap is vent port, and you can top it off there if you need to. Turn the stern drive all the way to the left (port) side and you'll see a flat head screw on the starboard side almost parallel with the pivot caps. That's the drain (messy as all get out) and fill.

​So just pour the oil into the top until full?

 

[southkogs]

Your stern drive has two gear cases. The upper gear case can use whatever gear lube you like. But the lower unit in an electric shift MUST be type C. THIS stuff is what I used.

On the bottom of your lower unit (under the "bullet") there is a port (flat head screw). There is another one in the photo you posted above: It's that hole just above the anti-cavitation plate. Fill from the bottom port, let the upper port be the vent.

Fill the upper gear case using the side port, but once you're mostly filled you can top it off from the top port.

 

[BudL1te]

"On the bottom of your lower unit (under the "bullet") there is a port (flat head screw). There is another one in the photo you posted above: It's that hole just above the anti-cavitation plate. Fill from the bottom port, let the upper port be the vent."

Got it, I thought I felt under there for anything but perhaps not.

I will look at it this afternoon.

Thank you for the tip on the type C oil in the bottom. I will make sure to get it.

Can Lucas additive be used in the upper and lower?

 

[southkogs]

I honestly don't know the real answer to that, but I would suggest against it.

You're lower unit is working via electricity, and you don't want anything in there that will compromise that charge (that's actually the reason for having to use TYPE C). The upper is gonna' leak on you. In theory they should seal up and not leak, but I've always been pretty religious about checking the lube in the upper. I probably changed mine at least twice per year to stay ahead of intrusion. That seemed to be consistent between the two uppers that I had - and I know the second was pressure tested because I watched.

There may be a "sure, go ahead" option - but I don't know for sure.

 

[BudL1te]

I honestly don't know the real answer to that, but I would suggest against it.

You're lower unit is working via electricity, and you don't want anything in there that will compromise that charge (that's actually the reason for having to use TYPE C). The upper is gonna' leak on you. In theory they should seal up and not leak, but I've always been pretty religious about checking the lube in the upper. I probably changed mine at least twice per year to stay ahead of intrusion. That seemed to be consistent between the two uppers that I had - and I know the second was pressure tested because I watched.

There may be a "sure, go ahead" option - but I don't know for sure.

I took your advice and just used what the shop recommended.

On a side note, the mechanic told me that Transmission fluid (Don't recall which type off hand) can be used in the lower end as it does not conduct electricity. As C type was not readily available to hand, I took his advice and it seems to work.

 

[southkogs]

I've heard that about the ATF. I can't tell you for sure ... and I've got some fuzzy recollection of a difference that made it better to hunt up the Type C stuff and use it. I would order it from iBoats:
https://www.iboats.com/shop/sierra-gear-lube-type-c-32-oz-18-9620-2.html

And just hold some on hand.

But it's possible the ATF will be just fine.

 

[BudL1te]

Perfect, Thank you.

 

[kenny nunez]

You asked about the red plastic plug facing forward on the exhaust housing. There is a zerk fitting inside to grease thr swivel bearing. The plastic plug usually breaks apart when you try to remove it. Do not worry if it breaks as OMC eliminated them on the later models.
ATF is a good substitute for the type “C”. The original type “C” lubricant that OMC used was made from Sperm Whale oil and was discontinued in the early 70s. Just a bit of trivia.

 

[BudL1te]

I thought I heard that about the whale oil too.

I think I will throw some grease in there too.

Thank you.