water in lower unit

[longshanks]

I am in the process of winterizing an '06 50HP outboard. The lower unit oil is a milky green colour. This indicates to me that a small amount of water is getting in there. There were no metal particles on the magnet, nor was there any water that came out when I pulled the drain plug. Gears appear to work smoothly, and there are no visible cracks in the lower unit. 37 hours total running time since new!

Leg oil was changed once or twice already, and the little washers may not have been replaced. Would this be a cause of water getting in there? Should I have the unit inspected by the dealer? Or should I replace the washers and keep an eye on er?

 

[Bigjohn1]

Re: water in lower unit

Yes, the "used" washers could be the culprit but maybe not. If it were mine, here's what I'd do to make sure: Obviously, replace the leg oil and place new gaskets on the various plugs when changing that oil. Take the boat for another run and then drain the leg oil again. This should be a good indicator if the gaskets/washers were the culprit.

 

[longshanks]

Re: water in lower unit

thanks Bigjohn

I'm going to replace the lube and put in new seals on the drain/vent plugs. Then run it next spring, and check after 5 hours or so.

Thinking that this may be normal, after reading the following on Merc's website:

Note color of gear lubricant when draining. If the color is white or cream it MAY indicate the presence of water in lubricant. Gear lubricant which has been drained from a gear case recently in operation will have a yellowish color due to lubricant agitation/aeration. Gear lube which is mixed with assembly lubricant (Special Lube 101 or 2-4-C w/Teflon) will also be creamy white in color. This is normal and should not be confused with the presence of water. If water is suspected to be present in the gearcase, a pressure check of the gearcase should be completed by an authorized dealer. Pouring a portion of the gear lubricant into a glass jar and allowing the lubricant to settle will allow any water in the lube to separate and settle to the bottom of the jar.

 

[Bigjohn1]

Re: water in lower unit

Good points being made. I couple of things can come into play though when making judgments about the "shade" of lower unit oil. Some brands are naturally light colored as compared to other brands. A perfect example of this would be a comparison of Penzoil 80W90 versus Mercury Premium Plus. The former is amber colored and the latter is dark blue.

After a while, you get used to how your particular oil should look. I think you can tell a difference between oil which has been contaminated with water and oil which is simply agitated or aerated. Good luck and watch it closely.

 

[Texasmark]

Re: water in lower unit

Draining after running can mislead you also, especially with Pennzoil or other honey colored lube. I like the suggestion to take a sample of oil and let it sit for a week. Any water will fall to the bottom of your sample vile.

When you go to the Merc dealer to get seals, get several sets. Then you'll have them handy when you need them so that you can put fresh in every time you pop the screws.

Mark

 

[longshanks]

Re: water in lower unit

I drained it completely, 2 days ago, and have re-filled it with new oil. I bought a dozen seals from the dealer, and have replaced the 'old' ones, even though they were not that old.

The oil I drained looked about like pepto bismol, only it was a nice shade of minty green/yellow. I've set some of it aside in a clear container, and waiting for the water to settle out, although none has as of yet.

I'll re-check it in the spring, but I think all is well.

thanks for the input guys.

 

[longshanks]

Re: water in lower unit

resurrecting this thread again, to see if anybody has any ideas.

I drained the oil again, and same result; even after running it once, the lower unit oil goes milky yellow/green/opaque. I've been replacing the washers every time I change the oil out, and I pressure tested the lower unit with a bike pump, and it holds 15PSI with no noticeable drop in pressure after 5-10 minutes. I've let the oil sit for a few days after removing it, and no water settles to the bottom...

Would the rest of you guys just ignore this? I keep thinking that oil should be clear.

 

[j_martin]

Re: water in lower unit

Modern LU lubricants have a pretty strong detergent component that will hold a considerable amount of water harmlessly and indefinitely in suspension. That's especially true of the high performance lubes.

If you drain the oil after the motor has not been run for several hours, and it's milky, something's wrong.

It could be as simple as not leaving enough head room over the gear lube for expansion. Follow the instructions explicitly for your engine. For example on my XR4 I'm to fill the unit from the bottom plug till it overflows, then allow 1 - 2 oz. to drain before I button it up. That's for the head room.

Without enough head room, it'll force a very small amount of lubricant past the seals (into the lake, you'll never see it) when you run it. When it cools down, the lubricant will contract and put a high vacuum on the seal, sucking in a small amount of water.

hope it helps
John