Filling gear lube in OMC Cobra

[dellsboater]

Read the post on filling correctly for the cobra. Wanted to check the level on a boat I just bought. Could not get dipstick out, so removed cover. Level was an inch below reading on the dip stick. It is very dark,almost black. Previous owner said changed this 2 weeks ago during winterizing.
Also noticed a little leaking from left side on outdrive, on the big plug everone on here said do not remove. Tightened the screw (see picture) it was alittle loose...seemed to stop leaking. Noticed right side has decal over where this big screw would be....

So shold fluid be black if just changed?
Any other thoughts?

1988 OMC cobra outdrive

 

[Bluestream]

Re: Filling gear lube in OMC Cobra

It should not be black if it was just changed. Maybe he put some Moly additive it, but I doubt it. Do not mess with the OMC mystery screw located behind the Cobra plaque(s). There is no oil in that area. Do a search on that...

 

[HT32BSX115]

Re: Filling gear lube in OMC Cobra

Previous owner said changed this 2 weeks ago during winterizing.
Also noticed a little leaking from left side on outdrive, on the big plug everone on here said do not remove. Tightened the screw (see picture) it was a little loose...seemed to stop leaking. Noticed right side has decal over where this big screw would be....

Funny how you just cannot always believe what the previous owner says huh?

There should only be water "leaking" from the "Do Not remove screw"...

That's all there is behind it. There is no 'screw' on the right side.


You should drain the oil and replace it.

It drains from the bottom drain hole and you fill it from the middle (fill-port) hole.

Fill it (to full) with the dipstick just sitting on top of its threads. (not screwed all the way in...........allows for a slight over-fill)

Then run the drive. Subsequent checks are with the dipstick screwed all the way in.

regardless of where the oil was on the dipstick was, were the gears or upper bearings uncovered?

Use any good marine type lube. Mercury HP gear lube, Volvo Penta syn, Mobil1 syn gear, Amsoil syn marine gear lube are all good.

Mercury HP and Amsoil claim to be designed to handle small amounts of water contamination. They probably all do just fine.

 

[dellsboater]

Re: Filling gear lube in OMC Cobra

No the gears are about half submerged. Can you tell that in the picture, or is it too dark?

 

[kmarine]

Re: Filling gear lube in OMC Cobra

While you have the cover off I recomend removing dipstick from plate cap. Replace dipstick if necessary. You can still use the dipstick to check level. Wipe off, place drive cap on upper drive, pull up and check level. I always fill from bottom on cobra drives. The don,t mess with screw has only water behind with and are a Joy to put back in when removed. I have had customers come in with them removed and could not get them back in. (I use fishing line arround backing plate to hold until I can get a few threds started, then pull out fishing line before tightening) as for leaking arround drain screw gasket. try a new one. If this does not work try an o ring.

 

[HT32BSX115]

Re: Filling gear lube in OMC Cobra

I always fill from bottom on cobra drives.

That's the best way to destroy a Cobra.


NEVER NEVER NEVER Fill a Cobra from the drain hole on the bottom.

The OMC service manual indicates to fill from the "Fill" port.

There are some that indicate it's "ok" to fill from the bottom until fluid appears at the FILL port, then continue filling from the fill port.

I suppose that works. Don't do it. Just follow the OEM service manual procedure. There is no reason to do it otherwise.

 

[LAC_STS]

Re: Filling gear lube in OMC Cobra

I filled my cobra from the bottom when I first got it. I didnt know any better at the time.

Nothing happened and I saw about a month later the correct way to fill it. I went and changed it again just incase, this time filling from the middle hole.



I dont get why people want to try to use the bottom hole. Even if it works the manual, which of course is written by the people who make the drive say to use the middle hole.

So whats the point of trying the lower hole? Cause thats how Merc does it?


Thats one reason I dont like the Seloc manual. They say numerous times "OMC says to do xxxxx this way, but we think you should do it this way."

 

[Lou C]

Re: Filling gear lube in OMC Cobra

The oil coming out of my Cobra has never been black, either when I used the OMC hi-vis or now that I've been using the greenish blue Merc Hi Performance gear lube. I'd change it....

 

[dellsboater]

Re: Filling gear lube in OMC Cobra

Yes will be changing it. I think I will fill from the middle plug, but this is not the big plug, right? The middle plug should be the same size as the bottom plug, right? I will fill from middle, with the top cap sitting there but loose. Then when I have put 64 oz in can lift off top to make sure gears are submerged, then tighten back on cap. Run drive, then check with dipstick....wouldn't this make sence? Why doesn't everyone leave the large top cap loose, so you can vissually inspect that you drained it all and that after filling, its right. Seems a little extra work to be sure you do not fry gears...just a newby so please correct me if I am wrong...

 

[HT32BSX115]

Re: Filling gear lube in OMC Cobra

So whats the point of trying the lower hole? Cause thats how Merc does it?

Well...yes. That IS the Mercruiser way.

My previous drive was destroyed twice by Four Winns dealers.

In the first case, they didn't bother to refill the drive at all!! It made it about half way around the lake before it seized.

In the second case, a different dealer filled it "like a Merc" and it made it a little further!


Each dealer replaced the drive each time with no "lawyering up".

If you fill a cobra from the bottom, you risk trapping a large enough bubble that eventually works its way to the top uncovering the upper gears/bearings......Does it happen EVERY TIME? maybe not......do you feel lucky?




For the life of me I don't understand why there are some people who insist on not doing it the way OMC instructs. Are you just trying to be different?

Why risk it on something that costs so much to repair/replace and in some cases (King Cobra), where certain replacement parts are simply not available?


I wouldn't do it by removing the top cap unless you have a new O-ring to replace it every time. You don't want that thing leaking. Just do it the way OMC says to do it.....It ain't Rocket Surgery!

 

[kmarine]

Re: Filling gear lube in OMC Cobra

King cobra has a seperate fill-porthole, not all cobra drives had them. You are also supposed to re check oil level after leting drive rest. I like to run short time,30 sec, and wait a couple of hours and then top off drive.

 

[Gary H NC]

Re: Filling gear lube in OMC Cobra

If that is connected to the 4.3 or 5.0 engine it should hold 64 ounces of gear lube.
Replace the large rubber O-ring on the top cover and the o-ring on the dipstick.
The drain and fill screws use the nylon crush gaskets...replace them too.

And yes,the middle "fill" screw is the same size as the bottom drain screw...

 

[HT32BSX115]

Re: Filling gear lube in OMC Cobra

King cobra has a seperate fill-porthole, not all cobra drives had them. You are also supposed to re check oil level after leting drive rest. I like to run short time,30 sec, and wait a couple of hours and then top off drive.

I don't know which Cobras you're talking about.

Even ( Sterndrive.info ) T.C. Electronics indicates to use the "Fill" port. AFTER the oil comes out of it......They don't delineate between the "King" and other Cobras or "Some" Cobras.

[FONT=Arial,Helvetica,sans-serif]Start off by locating the lower drain screw/plug on the lower gearcase. (It is on the stbd. side of the lower unit on the cone - shown in photo). Remove this plug using the largest blade flathead screwdriver available. Quickly insert your oil pump as snug as possible into the drain hole.

[/FONT][FONT=Arial,Helvetica,sans-serif]Locate the upper drain screw/plug (shown in photo), and remove it using the same flathead screwdriver you used to remove the lower drain screw. Begin pumping oil into the lower drain hole, and carefully watch the upper drain hole until you see the oil reach this level. When the oil just reaches the upper drain hole, close it up by inserting the upper drain screw. (DO NOT STRIP the screw when making sure it is tight enough)[/FONT]
[emphasis mine]


They then indicate to continue filling from the "Fill PORT"........................................






The above "procedure" is in direct conflict with the OEM OMC service manual instructions that I had because it said to fill the drive from the "Fill Port" (Upper drain screw above) FROM THE START

Others have been doing it this way above, for quite some time and it appears to work.

Stuart Hastings however in his excellent article on the cobra said the following:

When filling the Cobra with gear lube, use the middle fill plug, as shown in the Owners' Manual. Do not fill through the (bottom) drain plug! If you fill from the wrong port, you will probably trap a big bubble of air inside the vertical drive, and that bubble will eventually rise to the top. When it does, the upper gearcase gears will run dry, and self-destruct. As they say in the computer biz, "RTFM."

Since I DID "RTFM", I tend to want to follow it.

YMMV.....


Every so often, some new guy here comes on the forum complaining that his drive "failed" after de-winterizing. When we ask if the drive oil was replaced they usually say "yes". Then we ask how was it filled, the answer is usually the same. (filled from the bottom like a Mercruiser)


Get your hands on an OEM SERVICE MANUAL, RTFM, then follow the instructions.


It's as simple as that.....

 

[Don S]

Re: Filling gear lube in OMC Cobra

Just in case someone wants to see what it looks like in the OEM manual.

 

[kmarine]

Re: Filling gear lube in OMC Cobra

Thank you for the reply. I worked for a OMC dealer, and was evidently taught wrong by two master OMC technicians. No wonder they are out of business.

 

[HT32BSX115]

Re: Filling gear lube in OMC Cobra

Thank you for the reply. I worked for a OMC dealer, and was evidently taught wrong by two master OMC technicians. No wonder they are out of business.

No problem..... ALL of us are wrong at one time or another.(I think I am more than most!!)


My brother bought my boat (with the 460 King Cobra) new in Las Vegas in 1987. He ran it for about 20 years with no real problems EXCEPT for when he took it to 2 different Four Winns dealers to have them change the oil and other normal other yearly maintenance.

One of them flat did NOT bother to refill it with oil . That could happen anywhere I guess!! It's not OMC related I suppose..........


The other one DID fill it like a Mercruiser, and the result was pretty bad......

Four Winns in the 80's and 90's WAS pretty much ALL OMC/Volvo. I would expect that all the dealers would have had OMC people that "knew what they're doing" but now?

It's anyone?s guess. A LOT of the OMC people have moved on, retired, died, etc.....

ANYONE with a dog-clutch OMC Cobra should do their home work and absolutely ENSURE that someone working on it knows exactly what they're doing because, doing it wrong can cost them their drive......


Regards,


Rick

 

[Lou C]

Re: Filling gear lube in OMC Cobra

One of the great mysteries of marine mechanic work. Why do people think they are smarter than the engineers that designed the machine, and wrote the shop manual? Same thing with those who insist on doing winterizing by sucking AF up the drive method. If the engineers do not recommend it, why do you think you are more knowledgeable than them?

 

[GLENN M]

Re: Filling gear lube in OMC Cobra

i did a GM sponsered apprentiship,had to do a entrance exam.it was all comprehention tests if you couldnt read and understand amanuel you were out.they gave a series of test and after everyone theyd come in and send people home.asking peoples advice and friends is great but the proper service manuel is god,before making amistake beg borrow or steal the proper manuel.you will be miles ahead.

 

[bruceb58]

Re: Filling gear lube in OMC Cobra

i did a GM sponsered apprentiship,had to do a entrance exam.it was all comprehention tests if you couldnt read and understand amanuel you were out.they gave a series of test and after everyone theyd come in and send people home.asking peoples advice and friends is great but the proper service manuel is god,before making amistake beg borrow or steal the proper manuel.you will be miles ahead.

Did they require you to know how to spell? Does Manuel's family know you were trying to steal him?

 

[dellsboater]

Re: Filling gear lube in OMC Cobra

Did they require you to know how to spell? Does Manuel's family know you were trying to steal him?

Really, this is important to you? The guy is just posting......wow