How to tell water in lower unit oil

[trobinson017]

Hey all,
I found an oil stream on my lower unit's skeg below the prop. It looks as though it came from where the prop connects to the lower unit. I had a friend tell me it may or may not indicate a blown prop seal. He also said it could just be too much oil in the system and it's not being completely burned in combustion. He said to drain my lower unit oil to see if it had water in it, saying it would look milky white if water were present indicating a blow prop seal. I just did this and there was a slight milkyness to some of the oil but for the most part when you look into the bucket I drained the oil into it's almost pure black with maybe some slight brownish looking area coelesced into a small area of the bucket. As a whole it smells like commercial mosquito poison (if you live in the south you know what I mean). I checked another website and it says a slight milkyness could be normal condensation particularly in hot, humid areas which it is down here in Fla. and that it's nothing to worry about.

So, I guess I just need to know if what I described sounds like water in the lower unit or just condensation? I really don't want to tear apart the prop area to try and find a blown seal but will if you all think it should be done. If not, then I'll refill the lower unit with the kit I just bought and go boating and check the lower unit again in a few months. I'll also keep an eye out for the oil "leak" if that's what it really was.

What do y'all think?

Troll

 

[trobinson017]

Re: How to tell water in lower unit oil

I should also point out the original oil "stream" was not a running stream of oil, but more like it had been a slow leak. It was wet and had a drip just hanging from the bottom of the skeg. I wiped some off and it smelled like burnt oil or grease. Thought this might help.

Troll

 

[OptsyEagle]

Re: How to tell water in lower unit oil

I suspect that you just have some unburnt exhaust oil dripping down, which is normal.

You could try putting the LU oil that you drained out, into a glass jar for a few days. Any water in it should seperate and move to the bottom of the jar. If you can't see it very well at the bottom of the jar then I would say that you don't have any.

 

[Harker]

Re: How to tell water in lower unit oil

The stuff on the skeg is probably unburned oil/gas dripping out of the exaust housing..when you change the oil in the lower unit, use new seals on the screws. Usually if there is a water problem the old oil looks like cappacino but your oil sounds really old and burnt. After running with new oil, drain a bit and see what it looks like.

 

[samo_ott]

Re: How to tell water in lower unit oil

I agree, it does not sound too bad. I'd change the LU oil and then check it again soon. If you're really concerned, use synthetic LU oil as it works much better with water in it to save your gears but the color does not sound bad. Post a pic of the oil would also help (if you still have it). As they say... it's worth a 1,000 words!

 

[Gary H NC]

Re: How to tell water in lower unit oil

Pull the prop off and see if you have any gear oil residue around the shaft.
Is the dripping oil black or brown or green? If its black its most likely unburnt fuel oil mixture.Brown or green its probably lower unit lube.
The foul smell of the gear lube is normal.It stinks when its new...

 

[trobinson017]

Re: How to tell water in lower unit oil

Thanks for all the info, folks! Based on the feedback here I think I'll refill the LU, operate it for a month then recheck it. The oil that was dripping down the skeg was black and sort of thick which sounds like unburnt oil. I'm hesitant to pull off the prop as I've never done it before. I do have a prop wrench and some cotter pins but my comfort level is still pretty low. I'm trying to find an experienced buddy or two locally that can show me how to do it.

Thanks again for the great feedback. I'll post again when I confirm either a leak or no leak.

Troll

 

[trobinson017]

Re: How to tell water in lower unit oil

I just realized I never stated what my motor is. It's a '99 Johnson 130 Oceanpro on a 21' Seaswirl Striper CC. They came together new when I bought the boat out of court probate in 2003, meaning I'm the first owner (boat was in storage from '99 to '02). Not sure that makes a difference given the topic but thought I'd throw it in there anyway.

Troll

 

[ezeke]

Re: How to tell water in lower unit oil

Worn out gear lube is black and stinks. Your plan to run the motor with new gear lube is the way to go.

If water is in the oil after recently running it, the gear oil is creamy looking. If the motor has been sitting long the oil will float on the water and you will get water when you remove the lower plug.

 

[HighTrim]

Re: How to tell water in lower unit oil

Make sure to change the gaskets on the drain and vent plug when you do this, it is the number one spot for water intrusion. You could always flush the lu with kerosene or diesel fuel to clean it out before refilling it with oil. ANd like Ezeke stated, the water will be at the bottom of the lu, so it will come out first, watch for it. Also check the drain plug for any metal shavings and clean it off, it is magnetized.

 

[iwombat]

Re: How to tell water in lower unit oil

Look again at ezeke's post.
The _water_ will be a the bottom of the LU, and it will come out first when you pull the drain.

Oil floats on water.

 

[HighTrim]

Re: How to tell water in lower unit oil

ooops, thanks for pointing out the typo wombat , i edited it.

 

[trobinson017]

Re: How to tell water in lower unit oil

Thanks again all! I had already drained the LU before posting this thread but I can say no clearly identifiable water came out when I pulled the plugs. The boat has been idle for about a month so the separation should have occurred. I have new seals/washers for the plugs and will refill the LU today and take her for a spin.

Thanks again!

Troll

 

[LubeDude]

Re: How to tell water in lower unit oil

I like to use auto tranny fluid to flush out a lower unit. I fill it with fluid and then run it in gear on the muffs for about five minutes. Do not do this if there are children or pets in the area for obvious reasons. This works very well.

 

[TheOilDoc]

Re: How to tell water in lower unit oil

I wouldn't recommend flushing the lower unit with anything like transmission fluid, diesel, etc. I certainly wouldn't recommend running it in gear that way.

The main reason being that you can never get all of it back out. What remains in the LU will work against the new oil by changing its viscosity, anti-foaming properties, and overall performance as a high pressure gear lubricant. Seals, particularly on older outboards, could even be jeopordized. Some contamination could become dislodged and actually cause worse problems.

Do a good drain, with the LU in the best tilt position for draining. Possibly let it drain over night. Refill with a quality LU oil. Continue to change the LU oil frequently, maybe after the first run or two, checking for water and contamination. When you feel comfortable with the look of the LU oil, extended your interval back to what the manufacturer recommends.

 

[trobinson017]

Re: How to tell water in lower unit oil

Just a quick update. I've run the the boat three times since draining/refilling the LU. One of the runs was about 4 hours with different speeds and a couple stops during which the motor was shut off. I haven't seen any evidence of oil leaking at all. I will take the advice of changing out the oil again, probably within 2 weeks (maybe another 3 runs total). BTW, someone mentioned replacing the washers on the fill and vent screws before reinstalling them. I couldn't find any to fit my LU screws at any local boat store which seems ridiculous in Florida. The old washers are a pretty thick plastic so I went ahead and reused them as I really didn't want to wait much longer to run the boat. I did a Google search to try and find the washers online but am coming up empty. Does anyone have a good online store for such things?

Thanks again to all of you for your advice. You are all helping me to become a more knowledgeable, confident boater.

Troll

 

[dajohnson53]

Re: How to tell water in lower unit oil

... BTW, someone mentioned replacing the washers on the fill and vent screws before reinstalling them. I couldn't find any to fit my LU screws at any local boat store which seems ridiculous in Florida. The old washers are a pretty thick plastic so I went ahead and reused them as I really didn't want to wait much longer to run the boat. I did a Google search to try and find the washers online but am coming up empty. Does anyone have a good online store for such things?

Thanks again to all of you for your advice. You are all helping me to become a more knowledgeable, confident boater.

Did you ask at the parts counter at your local Evinrude/Johnson dealer? I'm very surprised that they don't have the gaskets(washers), I've always been able to get them, even for very old engines. They aren't generic items though, you usually have to get them at the parts counter, not out in a bin or on display.

A lot of times, I've found it OK to re-use the washers, but if you do get water in there, you won't know if that's the source or not. Good luck.