Water In Lower Unit, Help Please

Epitome

Petty Officer 3rd Class
Joined
Sep 9, 2008
Messages
98
Bought my first "big" boat in September, 1998 Trophy 2503 Center Console with a 1998 Mercury 225hp 2 stroke EFI motor. Lower unit was pressure checked and checked for water when I got it. We used the boat 3 times and went through less than half a tank of gas total (150 gallon tank). When I pulled the bottom plug on the lower unit to change the oil today I was horrified when about 1/4 to 1/3 of a quart of water came out followed by the oil (boat has been sitting for 2 weeks). There was metal on the drain plug magnet. So-I let it drain very well then filled it through the top hole until the hand pump I was using had built up some pressure. Just above and forward of the top plug is a hole in the case. Some oil came out of that hole. I then drained all the fresh oil out very well and refilled it from the bottom hole. Prop spins smooth and tight and we never noticed any problems when we were using it. Being in the Northeast the boat won't come out of storage until March. What should I do next?

Note: The motor was always in fresh water and was very well maintained. It was stored 8 months out of the year indoors. It runs great and looks to be in mint condition other than this problem now.
 

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Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,930
Re: Water In Lower Unit, Help Please

This is a common problem as the 3.0 liter unit uses a plastic housing to hold shift shaft seal. These gearcases if over pressurized when testing will pop the seal upwards causing it to take on water. Now that you added oil it has popped the rest of the way and leaking into upper housing area and oil is draining out water drain hole casting. This is a simple fix as seal can be pushed back into place and use Loctite 271 as they do at factory to hold it in place. The seal is #16 in attached diagram...
 

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Epitome

Petty Officer 3rd Class
Joined
Sep 9, 2008
Messages
98
Re: Water In Lower Unit, Help Please

Thanks for the help ;) How do I gauge how much, if any, damage there is? Is it just a matter of fix the leak and run the boat and see if everything seems ok? I plan on using the boat quite aways from shore (10-30 miles) so I need to trust it. i do have kickers but pushing that boat 30 miles on a 15 hp kicker isn't my idea of fun. Thanks again.
 

Epitome

Petty Officer 3rd Class
Joined
Sep 9, 2008
Messages
98
Re: Water In Lower Unit, Help Please

Any other thoughts?
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,930
Re: Water In Lower Unit, Help Please

I would just repair the seal as described and fill with a good synthetic gear lube by Merc,Luberplate,Serria. I use the Serria fully synthetic(18-9680-2) in all my customers and it looks as good a year later than the day it was put in.
 

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