HOW MUCH WATER WILL TURN GEAR OIL WHITE

Just changed the prop shaft seals on our 96 merc 115 and then did a 1/2 hr test run.
Arriving back home we noticed that there was a small trail of milky oil coming from the lower drain plug. The plug was not in real tight. We thought we had really tighened the plug, but apparently had not.

Removed the plugs and pure white oil drained from the lower unit. Just how much water will it take to turn the oil white, one drop, two drops, three drops does anyone know?

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Can anyone help Bill out here. I am a buddy of his and we have been working on this lower unit for a week and it still has water in the lower unit. Just to let you all know that I call myself the one armed lawyer because that's how it feels working on engines for me some times. Like I have one arm. But I realized recently I really like to work on them...or watch Bill work on them and feel like i am doing something. o

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

It does not take much. Oil is cheap, I would drain and change the oil again

Mike

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Make sure the plugs have gaskets or O-rings on them and that they have not been cross-threaded and thus not sealing tight. Since you worked on the prop seals, it's possible that operation was done incorrectly. It is not important how much water got into the oil. It is important that you discover how it got in and fix it. If after one run the lub is contaminated, there is obviously a serious leak. How about the condition of the drive shaft seals (not to be confused with the prop shaft seals)?

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

With out a pressure and vacume test a seal repiar is a shot in the dark

It needs to pumped up with a pressure tester and then you should se the leak IF not you use some spray to look for bubble from small leaks


Tommays

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

tommays said:

With out a pressure and vacume test a seal repiar is a shot in the dark

It needs to pumped up with a pressure tester and then you should se the leak IF not you use some spray to look for bubble from small leaks


Tommays

Click to expand...

How much pressure and for how long should it hold to be considered good seals?

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Bill said:

Just how much water will it take to turn the oil white, one drop, two drops, three drops does anyone know?

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It really depends on the oil's individual saturation point, how much oil you have, and the temperature and pressure conditions the oil is under.

Since you are seeing a visual discoloration of the oil (white), it indicates that the oil is supersaturated resulting in an emulsion effect. Some oils with high emulsifying agents can handle emulsions up to 10% water. While oils like low-additive industrial lubricants will hold no more than 0.5%.

For those who are not sure if they are getting water in their oil, there is a simple test you yourself can do. All you need is a hot plate that can reach 300F (accurately) and a dropper.

Use a clean dropper to place a drop of your oil on a 300F hot plate.

If you don't observe any crackling or vapor bubbles after a few seconds then no emulsified water is present.

If you observe very small bubbles, about .5 mm, that quickly disappear, then you have about .05 % to .1 % water present.

If the bubbles get to about 2 mm and appear to be in the center of the oil, and grow to about double their size, and then disappear, you have about .1% to .2% water present.

Water levels above .2% will produce the same results as above, but the process (enlarging bubbles disappearing) will repeat itself up to two more times.

For yet higher moisture levels, violent bubbling and crackling may result.

This method isn't quantitative, and different oils will give slightly different results. Levels of .1% would be a major concern. Regardless, it's a good "back yard" test that will give you an idea if you have moisture in the oil or not.

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

After we changed the two prop shaft seals and the carrier O ring we pressure tested it and sprayed soapy water all over and saw no leaks.
Gonna flush it out with 30 wt car oil then drian and refill it with gearcase oil, i want to try to get all that white oil outa there.

Back to my original question, Will a few drops of water turn the oil white??? I realize with all those gears churning as we drive it must be like a blender inside that lower unit

I just realized something please correct me if I am wrong, but with the water pump on the lower unit and the lower unit on the bench and I pressurize it I will not be able to see if the driveshaft seal is leaking because that is below the water pump and any leak with bubble into the water pump housing outa sight. Is that correct??????

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Bill said:

Back to my original question, Will a few drops of water turn the oil white???

Click to expand...

Sorry I wasn't clear enough Bill.

Your question has a lot of variables....how well your particular oil emulsifies water (additives, etc), how much oil your lower unit holds, the temperature and pressure of the oil, and what you consider a "drop" of water to be.

Not knowing these things, I will try to give it my best hypothetical stab.

I'll assume your gear case oil has a water saturation point of about 5000 ppm. This would not be uncommon for basic gear case lubricants. If your using a special marine gear oil, it may be higher.

I'll assume your outboard gearcase holds bout 650 grams of lubricant (about 23 oz). That should be close.

A "drop" of water really has no measurement (the ocean can be considered one big drop). But I'll assume a "drop" of water is about .025 grams. Close for an eye dropper amount.

I'll also assume the gear oil is at ambient temeprature and pressure. As the oil cools the saturation point drops along with a smaller margin.

So, one drop of water would pose .025g water/650 g oil. This equates to less than 40 ppm water. A "few", or lets say 3, drops of water would equate to less than 120 ppm water. That is not enough water to cause the saturation (white discoloration) that your are experiencing. You would need about 125 drops of water to saturate the oil in this example. That's probably over a teaspoon. But I have a feeling your levels of water are much higher than the saturation level of your oil (ie: more serious leak).

Hope that helped.

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Without removing the water pump assembly you would not see a drive shaft seal leak but you might hear it with the lower unit under pressure.

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

If you're getting that much water in the gearcase after replacing propshaft seals, that's obviously not the problem.

A leaking shift shaft seal (unless it was absolutely gone) wouldn't cause such rapid water intrusion into the lower unit/gear oil.

You really need to pull the lower unit, disassemble the water pump, and check out the driveshaft seals.

When driveshaft seals leak the pumping action of the impeller will actually pull oil out of the lower unit, and water of course takes place of the oil.

I'd expect this amount of leakage to show up on a pressure check, if it ain't driveshaft seals it's some other type of strange failure.

HTH and let us know what you find..............ed

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

My 150 just came up for the winter layup with a similar problem so I have been delighted that you raised the question as I have been somewhat concerned. I was assured that because the level of "fluid" in the gearbox hadn't risen since the service last year that the amount of water in the gearcase was minimal, although the oil was emulsified. In my case it was the seal under the water pump that was leaking plus a badly pinched drain plug seal. Hopefully all is well now with mine so good luck with yours.

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Thanks for all the positive feedback everyone. With special thanks to Rear Admiral Silvertip. YOu were right on. When we pressure tested the lower unit the air was whistling from under the water pump. Bill and I repleaced the drive shaft seals and are now anxiously awaiting our test fun to see if we fixed the problem. So to sum up Bill Kubiak and I have repleced the prop shaft seals and the drive shaft seals. Pressure tested the unit and everything seems to be sealed with the exception of a little bit of air escaping from the prop seals but ONLY at 20 PSI.,,,at 15 and under there is no leak.

thanks again for all your help and when we take her out next weekend we will post an update

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

I guess when we hit 20 PSI we overcame the prop seals ability to seal. We also changed the gear shift seal while we had it apart. Thanks again for all the advice and help.

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Maybe some with knowledge will chine here, but I think that is way [colour=null]too much PRESSUE [/colour]to be using for a pressure test. Obviously it does not leak now so I would think you will be alright with it.

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

I'm thinkin' 12 PSI is more than adequate for a lower unit seal leakage test!!!!

Give 'er a shot, I bet you'll find your leak is cured.........ed

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

hello! 12-15 psi is what i hear

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

OK FINALLY TOOK THE BOAT OUT. TO SUM UP. WE REPLACED THE DRIVE SHAFT SEALS AND THE PRO SHAFT SEALS. ALSO CHANGE WATER PUMP. THE OIL IS NO LONGER WHITE. BUT I THINK THAT'S IT'S NOT 100 PERCENT OIL. IT'S 100 PERCENT BETTER BUT I CAN TELL THERE IS STILL SOME WATER (VERY LITTLE ) IN THE OIL, THERE IS NO CHANGE IN THE COLOR OF THE OIL...IT'S JUST APPEARS "LIGHTER" IN COLOR THAN WHEN WE PUT IT IN. WHAT DO YOU ALL THIINK? i WAS THINKING IT MAY HAVE BEEN SOME LEFT OVER WATER IN THE LOWER UNIT BEFORE WE SEALED THEH DRIVE SHAFT????

Re: HOW MUCH WATER WILL TURN GEAR OIL WHITE

Ok we just returned from a test drive and drained the oil after 30 min of driving it around.
it was mostly clear with a swirl of white mixed in with the oil.
I am guessing that this is some residual that did not drain off the case and gears when we chged the oil.
Will know better after the next test drive.
Waddayathink gang??????