Milky oil in out drive

ijust noticed i have milky oil

ijust noticed i have milky oil in out drive. is it possibal that water could get in through ginbal housing . i have ran boat several times this year an have had no problems but this past weekend when i was going over boat i noticed oil coming out of small weep hole on lower unit. so i then checked oil at dipstick an oil is very milky. any sugestions would be great or where water could possilby getting in thanks john

"If the drive bellows is leaki

"If the drive bellows is leaking, water will leak into the outdrive. The lipseal on the input shaft is designed to prevent oil from leaking out but it does not keep water from leaking in.
This is one possibility."

"There are a number of ways. A

"There are a number of ways. Also a very common is either one or more likely several internal seals are leaking. Also have seen several examples of the water passage housing cracking. If you get to the point of removing the outdrive, do a pressure test of the lower unit. The bubbles will tell you what is wrong."

ijust removed prop an i found

ijust removed prop an i found fishing line wrapped around prop shaft .is it possible that line caued a breach in seals on shaft. also i had renoved out drive several tines this off season . i replaced gasket once so could that gasket be bad thanks john

The dip stik is on the upper u

The dip stik is on the upper unit is it not? You're upper unit needs new seals.

"The prop shaft has 2 seals ba

"The prop shaft has 2 seals back to back, one to keep the oil in and one to keep the water out, nothing takes those seals out quicker than fishing line. I would replace those seals and then do pressure/vacuum test."

"Just had same problem - weep

"Just had same problem - weep hole had a drip, when I drained the stern drive the oil was milky indicating water. I plan to pull the drive in any case due to a 'lost nut' due to removing one of the screws just above the lift pistons that are normally covered by a logo plate (OMC Owner's Mistake Number Two . Thanks for the posts re possible causes. Two followup questions. 1) Is there a recommended technique for doing a pressure test using a regular tire pump and gauge? 2) If there's no easily observed cause (eg bellows leak or fishline), is the recommended procedure to get a complete kit with all the internal seals, and replace them all rather than try to find and fix individual ones?"

1) Guess you could use a t

1) Guess you could use a tire pump. Just don't put too much pressure or you will cause the seals too fail. Mainly looking for bubbles to tell you where the leak is. Or ISN'T.
2) The proper procedure is too find the cause of the problem. Replacing all the seals and water passage housing is of no good (and a lot of work) if it is not the problem. Also consider that some people have damaged their outdrives in doing that work or left themselves a new leak because of not getting something right. So find the cause of the problem.

"This is to report a successfu

"This is to report a successful retrieval of the 'lost nut' under 'OMC Owner's Mistake Number Two Screw' on my 89 OMC Cobra drive. Here are a couple tips and pix that may be helpful.
1. I made a dolly from 2x6's and heavy duty caster wheels, with two angle strips to clamp down the stern drive plate. The eye bolt sticking up from the drain plug hole was something I added to use a chain host but ended up doing a dolly instead. Left it in while working anyway, it provided a handy 'handhold' to help maneuver the stern drive. Just don't tilt up the stern drive with the eye bold in, it could hit the back of the boat!
pulling the stern drive away on the dolly"">
I used the boat drive tilt switch to lower the drive so the plates were horizontal and just above the dolly, then used the boat trailer jack to lower it onto the dolly and attached metal angle strips to clamp the plates to the dolly. Worked like a charm, very easy to move. Go slow after removing the 6 nuts when you pull the stern drive away from the boat, and make sure the gasket doesn't tear (unless you thought ahead and have a new one to put in).
home-made dolly for removing cobra stern drive"">
2. It was easy to fish out the lost nut (see pic)
the lost nut as seen in the left stern drive water channel""> Putting it back in was harder to reach. I used an open end wrench to hold the flat nut (it's a bar about 1 1/2 inches long) and wrapped the end of the wrench holding the bar with electrical tape to hold the nut steady while inserting it (see pic). My wife also suggested cutting a piece of cardboard and sliding it in next to the wrench to prevent the nut from falling further into the stern drive through a water access hole.
using an open end wrench and electrical tape to hold and reinsert the nut"">
3. I looked for a leak, and the only obvious problem was the gasket where I removed the stern drive had a small tear/defect. Not having a new gasket on hand, I bought a couple tubes of blue gasket silicon (like formagasket) and applied that liberally to the defect and in fact over the entire gasket, before reattaching. Line things up carefully and slowly turn the u-joint if necessary while pushing in to reinsert the drive shaft into the boat motor spline, you may have to try this a few times before it goes.
line things up carefully and slowly spin the u-joint while pushing in to reinsert the drive shaft"">
This has shown no sign of leaking since, but I've only used the boat a few times so there may yet be some other problem and I'll check the oil for milkiness to be sure it's ok. At least now I have a nice dolly if the stern drive has to be removed again. "

Good job Paul....nice pics too

Good job Paul....nice pics too!

What happened to the painted surface around the area 'OMC Owner's Mistake Number Two Screw' ??

"Bob - the surface coating pee

"Bob - the surface coating peeling/flaking around the 'hidden' screw that you can see in the picture, has been there for many years, not sure what caused it. The Cobra decal that originally covered the screw has been missing for many years too. Would it be appropriate to give it a coat of paint, or some other treatment?"

"Well...it's up to you of

"Well...it's up to you of course but I would probably give it a coat of the zinc primate (primer) and then touch up with some OMC gray, I'm sure some of the dealers still have some of the spray bombs in stock. You might even want to replace the Cobra emblem which is still available through a dealer so that your not tempted to touch that screw again, although most only make that mistake once

Part Number: 0911848
Description: MEDALLION-COBRA"

Nice job Paul. It would be go

Nice job Paul. It would be good to put it in a new thread appropriately titled.

"That is a great job, especial

"That is a great job, especially the construction of the dolly. I have an outboard motor stand that I got when I bought a 75hp Mercury a while back. It now has the 50hp Mariner that I replaced it with on it, but I know what to do with it when I finally get off my arse and fix up and sell the Mariner. Thanks for the idea!"

"I am trying to rehab a 1986 t

"I am trying to rehab a 1986 thunder craft it has a 4.3 liter omc with a cobra outdrive it did not come with a prop so i bought one at a boat shop i also got the thrust washer and a splined washer the thrust washer and the prop slide onto the shaft ok but there is not enough spline for the splined washer i have a feeling i got the wrong prop it is 15x17 the only other marking on it is 391200 it is steel could anyone tell me what they have, or if some props are deeper than others .how to find the correct one? thanks"

391200 is an OMC PN for a 15 x

391200 is an OMC PN for a 15 x 17 prop so it should fit fine. Does the thrust washer sit down inside the lip around the hub in the center of the prop? Quite often the spline washer will only go on about halfway. I suppose it's possible that you may have an incorrect thrust washer that isn't allowing the prop to go all the way on.


You should really start a new thread about the prop instead of tagging onto this thread.