# Water in my Lower Unit?



## OSU_Fisherman (Mar 1, 2007)

I winterized my boat this past Tuesday and snapped a couple quick pictures of my Lower Unit oil as it was draining. The first picture (with less milky coloration) was taken within a minute after pulling the plug on the LU. The second picture was taken after about 10 minutes of draining and was the worst that the milky coloration ever was during the draining. Towards the end of the draining it looked perfectly normal with no milky coloration at all.

Right now the boat is in my parents heated garage but I'm moving it to my neighbor's non-heated barn shortly. I filled the gear case with new lube and did not notice any water coming out of the top vent hole in the LU when filling. Am I OK here? The LU will be worked on in March because of my ongoing reverse issues, so I assume any seal problem will be taken care of at that point in time.

I dont know if it would be helpful, but the motor is a 1989 Johnson GT150 outboard.


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## Bassnpro1 (Apr 6, 2004)

Jason, I wouldn't be worried by it. I just did my boat and had a small amount of discoloration too, but the amount of discoloration was not substantial in comparison to the amount of oil and the number of hours I put on the boat this year. I believe that a little bit of water will get in there throughout the course of a year and especially with older motors. Yours looks a little better than mine did and I feel fine about mine.

BTW its a sad day when you have to winterize the boat hopefully my boat will be back out in about two months.


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## ChampioNMan (Mar 17, 2009)

Doesn't look bad.There will be some discoloration with the oil ecspecially if it has been in the L/U all season.

Water will be in the bottom of the case............Did any water rush out as soon as you pulled the plug? 
I start the fishing season usually in March with fresh L/U oil and usually change it towards the end of June and finish out the season. Cheap insurance!

Have them pressure test your L/U while they have it in for repairs,while they have it apart they might as well replace the seals.Good time for a water pump replacement as well if its over 2 yrs old.


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## peple of the perch (Sep 13, 2004)

Water is getting in the lower unit. One of the seals are bad on the lower unit. Check to make sure the nylon seals are still on screws that you take out for the oil.


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## OSU_Fisherman (Mar 1, 2007)

peple of the perch said:


> Water is getting in the lower unit. One of the seals are bad on the lower unit. Check to make sure the nylon seals are still on screws that you take out for the oil.


Yep, the seals are on the screws. I replace them at the beginning of each season when I change out the oil when dewinterizing in the spring.


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## Fishers of Men (Jul 29, 2005)

There is a seal behind the prop in the LU, and if you get some mono or other line wrapped in there, it can cause leakage.


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## big_b16 (Oct 17, 2004)

Any water getting in your lower unit is not normal. That's why they have seals. There are seals on your prop shaft and on your drive shaft (under your water pump). One or both of them should be replaced if you've got someone tearing it down to get at the gears. A pressure test will find the culprit but I'm not sure if your wrench of choice has the ability to do it. If you don't know if they've ever been changed, just buy them and have the guy doing your gear work replace them. Should add no time to the labor charge...unless they bill by the minute, then add about 5 to pull the old ones and press the new ones in.


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## Searay (Feb 12, 2007)

I'am sure a quality mechanic will change the seals if going into it to do gear work, I myself change fluid mid season to check for water or metal particles... I like to use the blue gear lube easier to detect water. As for your concern on the lu your ok...


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## jay2k (Dec 21, 2005)

I wanted to bump this thread up cause I have a few questions myself. I just drained my LU fluid and it had a dark greenish color to it. I didn't see any water come out of the plug either, but it seemed a little "wet" (if that makes sense) to me. Sorry I have no idea on how to explain. I also seen that the rubber seal around the drain plug was stuck in the port and rotted out. The motor was stored completely vertical over the winter. There was also a small amount of metal on the magnet and in the bucket that the oil drained into. Is this something serious? I've never had problems in the past, and the boat was out once a week last year, but now I'm a bit worried. Should the prop be removed to look for bad seals? And how difficult is this to do? If anyone can post after reading this rambling please do..!! Thanks!


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## Workdog (Jan 10, 2007)

jay2k said:


> I wanted to bump this thread up cause I have a few questions myself. I just drained my LU fluid and it had a dark greenish color to it. I didn't see any water come out of the plug either, but it seemed a little "wet" (if that makes sense) to me. Sorry I have no idea on how to explain. I also seen that the rubber seal around the drain plug was stuck in the port and rotted out. The motor was stored completely vertical over the winter. There was also a small amount of metal on the magnet and in the bucket that the oil drained into. Is this something serious? I've never had problems in the past, and the boat was out once a week last year, but now I'm a bit worried. Should the prop be removed to look for bad seals? And how difficult is this to do? If anyone can post after reading this rambling please do..!! Thanks!


Mercury Premium/Premium Plus lower unit lube is dark green. Water in your lube will have a tan color to it. If you are just getting a slight amount of tannish swirl in your lube it should be no problem. When you drop the lube into a container, it can have a shimmery look to it that you might mistake for metal, but you should NOT feel chunks of metal in it. If you have some very light metal dust on your plug that is normal. Get a small knife blade or pick and completely remove the plug seal residue. Then, install plugs with a new gasket ring. Of course you will fill from the lower hole, etc. etc. Reply back if you do not know the lower unit lube procedure.


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## jay2k (Dec 21, 2005)

I checked the gasket rings on both the plugs and they are shot. I also checked 3 different hardware stores looking for new ones and nobody has anything like em. I bought some "O" rings, but the plug doesn't fit flush with the port. I need some flat gaskets and the only ones I have found have too small of a hole for the plug to fit. Where can I get some made for this situation?


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## Workdog (Jan 10, 2007)

jay2k said:


> I checked the gasket rings on both the plugs and they are shot. I also checked 3 different hardware stores looking for new ones and nobody has anything like em. I bought some "O" rings, but the plug doesn't fit flush with the port. I need some flat gaskets and the only ones I have found have too small of a hole for the plug to fit. Where can I get some made for this situation?


A Merc joint or West Marine. Those gaskets are specially made/sized by Mercury Marine for those plugs.


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## jay2k (Dec 21, 2005)

Thanks workdog. Will be heading up to Buckeye Sports tomorrow.


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