Foamy outdrive gear lube normal after use?

[Jeffdz]

hi all. I have a 1995 Cobra SX outdrive. I drained and refilled the gear lube with quicksilver 90w. After running the boat on the hose and muffs I pulled the dipstick and the gear lube looks foamy or frothy. Is that normal after running the boat? It doesn’t look milky just looks like a bunch of tiny air bubbles. If I pull the dipstick and wipe off and then recheck a couple times it goes back to solid blue color no bubbles. Is this normal or does this indicate some kind of water contamination or something else? I’ve never pulled the dipstick right after use before so I don’t know if this is normal or not. Any help would be appreciated. Hoping it’s normal. Thanks gentlemen (and ladies).

 

[southkogs]

LOL ... I've never had a dipstick on drive lube before, so I don't know. But air bubbles trapped in the lube from all of the gears churning seems normal to me. Especially if the lube looks right if you drain some out.

 

[Jeffdz]

Okkkkk. Not sure what you mean by that. As far as I know all outdrives have a dipstick to check fluid level. Has no one ever pulled their dipstick after using their boat or after running on the muffs?

 

[Jeffdz]

Also do the gears even turn when you are in neutral running off a garden hose and the water muffs?

 

[southkogs]

I've never owned an OMC Cobra. The Stringer I used to have didn't have a dip stick for the drive lube (some did though). As far as I know, my current Mercruiser doesn't have a dipstick for the gear lube. So - I have never seen my gear lube on a dipstick immediately after running the drive.

If I were to pull a dip stick immediately after running a drive - I would think that the turning of the gears would cause cavitations in the lube, thus producing bubbles. Ergo ... seeing that on the stick would seem normal to me.

IF I did see the frothy lookin' bubbles on a dip stick, but could later drain some lube off the bottom of the drive and it looked normal; I would take it that the lube was fine and acting within specs.

I don't know how the gear cases function when you're in neutral on a Cobra.

 

[Jeffdz]

Thanks Southkogs. Hoping someone has a cobra drove or a Volvo Penta sx that can chime in or check it after running off the hose and muffs

 

[Jonathan 88]

I have an OMC outdrive and I can tell you that the top 90 degree bevel gears and the vertical shaft of the outdrive spin in neutral. I can’t run mine today but I can do it as soon a possible for you.

 

[Horigan]

I have your drive and wouldn't worry about it. If it shows full after letting it sit a bit, then you're good. I've never checked right after running on muffs. It could be a bit of air that was trapped during refill that gets released during initial run.

 

[Jeffdz]

Jonathan 88 if you could do that for me that would be awesome! It would certainly put my mind at ease! Thanks so much guys! Appreciate all the help.

Horigan - it wasn’t just the initial startup after the fluid change. I took it out for a test ride too quick and it was the same thing after that as well. The fluid stays at the same level after it settles down after use.

Also, they say to top it off thru the dipstick, which I tried but the level never seems to come up. I’d put 2-3 pumps of gear lube in the dipstick hole which would basically fill it to the rim. Then it would settle into the housing after 15 minutes or so but the level never seems to move on the dipstick after. Repeated the 2-3 pumps probably 4 times but no change in level so decided to stop adding. I don’t see gear lube anywhere tho. I don’t believe it’s leaking anywhere

 

[HT32BSX115]

hi all. I have a 1995 Cobra SX outdrive. I drained and refilled the gear lube with quicksilver 90w. After running the boat on the hose and muffs I pulled the dipstick and the gear lube looks foamy or frothy. Is that normal after running the boat?

Howdy,

Yes, the input shaft always turns when the engine is running.......so yes the upper gears are also turning.

It's quite "normal" to have "frothy" oil for a while after a drain and refill. "Froth" is air bubbles in the oil (assuming there's no water) The fill procedure for some SX models talks about filling through the drain port and/or filling through the dipstick port. If you filled through the dipstick port, did you wait 15 min before checking the oil level?

(Filling that way will destroy a Dog clutch Cobra by the way..........NOT YOUR SX)

Once the oil heats up, the bubbles will rise to the surface quicker. If it's cold, it'll take longer. Simply running on "muffs" will not heat the oil sufficiently to make the bubbles rise any faster ...............



Did you follow to the letter the refill procedure (for your year model OMC SX) AND did you fill the drive with the
recommended amount of oil?

(It's VERY specific for the dog-clutch Cobras, DIFFERENT from your SX by the way and I only mention the Dog-clutch models here for the casual reader that might have a "Dog" and thinks this is the way to fill it........)

Let it sit over night, check the oil level and top-off as necessary and then run it on the water long enough to get the oil hot.

Then let it sit for a while before checking it.

Be absolutely sure you refilled it with the correct amount of oil that would be required after a drain. If you used a LOT less, there may be a bubble trapped in the drive. (this is unlikely if you followed the re-fill procedure for your model drive)

Cheers,

Rick

 

[Horigan]

Also, they say to top it off thru the dipstick, which I tried but the level never seems to come up. I’d put 2-3 pumps of gear lube in the dipstick hole which would basically fill it to the rim. Then it would settle into the housing after 15 minutes or so but the level never seems to move on the dipstick after. Repeated the 2-3 pumps probably 4 times but no change in level so decided to stop adding. I don’t see gear lube anywhere tho. I don’t believe it’s leaking anywhere

My OMC manual says to fill from the drain port with a pump, not from the top. That would explain your bubbles. If it were me, I would drain it and fill it properly from the bottom with the drive level until fluid comes out the fluid level port near the shift mechanism. My fluid has been bubble free using this method and it lines up with the dipstick full line.

 

[Jeffdz]

Thanks guys. I did fill it from the drain plug with a pump until it came out the hole up by the shift mechanism. Then it says to put both the drain screw and the screw by the shift mechanism back in and top it off through the dipstick hole. I did this probably 3-4 times waiting for the fluid to settle in between top offs. Fluid level didn’t really seem to come up though with 3 pumps each time. It ended up maybe 3/4 the way to the full mark on the dipstick. The manual says 2.1 quarts for a fluid drain and refill and I put all of that in there anyway. So I did fill it properly as far as I know according to the manual. Unless there was an addendum to the procedure some where along the way. I have seen some people say (that claim to be Volvo certified mechanics, since this drive is basically a Volvo branded with an OMC label.) that once the fluid comes out the top hole by the shift mechanism that the drive is full. They don’t mention topping off through the dipstick tube. Not sure if that is true or not but in my extensive reading I did come across at least 2 posts where the guys claimed to be Volvo certified and said such.

 

[Horigan]

Thanks for the clarification. I've never heard of topping off through the dipstick hole. I think if the level is between half and all the way full, you're good. Filling until fluid comes out of the full hole should get you there if the drive is level when filling.

 

[Jeffdz]

Thanks Horigan. I should mention that my fluid is bubble free when just sitting. It’s only right after running that it looks aerated. The tiny bubbles do settle out after about 10 minutes and it’s back to normal solid fluid with bubbles. I just want to make sure it’s normal is all

 

[Jeffdz]

With no bubbles* sorry

 

[HT32BSX115]

Thanks for the clarification. I've never heard of topping off through the dipstick hole. .

Not being a "Volvo Guy" and remembering my previously installed OMG 460 King Kobra dealer-caused drive disaster (from improper oil-fill...........I was a little surprised reading it in the Volvo SX service instructions too.

But here it is.... right from HERE:
https://www.manualslib.com/manual/917510/Volvo-Penta-3-0gs-Sx.html?page=66#manual

Oil. Replacement SX drive
Trim the drive to it's normal running position. Rem-
ove the oil dipstick (A). Remove the plug (B) on the
underneath of the propeller gear housing and let the
oil run out in to a suitable container. Reinstall the
plug and gasket. If oil is colored grey then water has
entered the drive. Contact authorized service per-
sonnel.
NOTE! Deposit the used oil at a properly designated
disposal site.
Trim the drive up slightly. Remove the rear cover by
removing the three retaining screws. Remove the oil
level plug (C). Top up oil through the hole for the oil
dipstick. Install oil level plug and lower drive to run-
ning position. Wait approx. 15 minutes to give the oil
time to run down. (The dipstick should not be instal-
led during the waiting time). Check the oil level. For
oil quality and capacity: See chapter Technical
Data

I still think you will have foamy oil for a short time.

BUT ABSOLUTELY ENSURE that you refilled the correct amount of oil.

If it's markedly less, you either didn't drain it completely or there's a bubble trapped inside.