Main Menu
Newest Members
marsh, Texas Torpedo, WTXBA806, robbiehoover, texasggm
108880 Registered Users
Top Posters
TexDawg 89600
hopalong 78895
Pilothawk 76935
John175® 68876
JDavis7873® 67392
Derek 🐝 61278
FattyMcButterpants 60904
Tritonman 58260
LoneStarSon® 54732
SkeeterRonnie 53597
Forum Stats
108880 Members
60 Forums
782851 Topics
10101572 Posts

Max Online: 36273 @ 01/23/13 02:34 PM
Topic Options
#12599267 - 01/28/18 05:17 PM Water in lower unit question
justchillin Offline

Registered: 05/05/13
Posts: 491
Loc: cedar creek lake
No water in the oil at the start of last season. I change it every year. Impeller went bad , so I replaced it. Only replaced the impeller though. My question is could not changing the o-ring on the impeller housing cause water to get into the lower unit ? May be a long shot , but before tearing down prop etc.. for other seals, just thought I would ask. Thanks for your replies in advance.

#12599303 - 01/28/18 05:40 PM Re: Water in lower unit question [Re: justchillin]
tmd11111 Online   content
Pro Angler

Registered: 04/30/17
Posts: 965
Loc: San Angelo
Changing it wouldn’t hurt but below the water pump assembly there’s two seals. One facing outward to keep water out and one inward to keep oil in.

#12599800 - 01/29/18 12:57 AM Re: Water in lower unit question [Re: justchillin]
Bobby Milam Online   content
TFF Team Angler

Registered: 07/13/14
Posts: 3579
Loc: Arlington
Yes it can. Easy enough to test. All you need is a bicycle pump with a gauge on it. Cut the screw in filler for your oil off and attach to the pump hose. Screw it in one hole and put screw back in the other. I can't remember the pressure but it isn't much, around 10 lbs I think. Spray some soapy water on both screws and look for bubbles. Leave it pumped up and check later to see if it held the pressure. If not and it didn't bubble at screw then it is inside gasket.

#12599830 - 01/29/18 05:32 AM Re: Water in lower unit question [Re: justchillin]
EastBay Boats Offline

Registered: 12/05/17
Posts: 30
Loc: Texas, 77414
When inspecting the gear case for water in the gear oil, and is wet/milky, hydro the gear case for leaks before you drain it, is the only way to prove it for water intrusion,5 pounds of pressure max to test, if it fails, purchase a complete seal kit and replace
979 323 9087/Howard

#12604844 - 01/31/18 10:24 PM Re: Water in lower unit question [Re: justchillin]
RickS Offline

Registered: 08/08/13
Posts: 213
Loc: Santa Fe NM
Don't replace anything until you pressure test and find the leak. I was getting water in my lower unit last season. I have a 96 Mercury 150XR6.I'm a master auto mechanic. So I did some research and watched some Mercury training videos. I drained my lower unit. Then installed lower drain screw. Purchased a mityvac elite hand vacuum and pressure pump kit. I just checked at tool topia .com they are $52.93. Attach this to the fitting you usually use to fill your lower unit. I had to put some Teflon tape on the threads of the one I had. Screw this to the upper vent screw. Remove your propeller if you haven't already. On mine I had a pretty good leak around the prop shaft seals. Spray around them with a water/dish soap solution in a spray bottle while pumping the mityvac. If your prop shaft seals aren't leaking than you'll have to drop your lower unit. Check around the shift shaft seal and then below your water pump. I don't have experience with these leaks yet. Pressure I recommend is 10 PSI.

#12605306 - 02/01/18 10:39 AM Re: Water in lower unit question [Re: justchillin]
gary purdy Offline
TFF Guru

Registered: 05/24/03
Posts: 11468
Loc: Littlefield Tx & Lake A. H. US...
First off the O-ring you are referring to is to hold the impeller key when installing the impeller on OMC`s and will not leak water into the lower unit. Look at your plug gaskets really good. They can cause a leak. Reason I always install new gaskets on the plugs. Other than that have it pressure tested as fore mentioned.
The world will not be destroyed by those who do evil, but by those who watch them without doing anything. Remember what He has done and remember that He is not done yet!-- GOD IS GOOD

#12607670 - 02/02/18 02:51 PM Re: Water in lower unit question [Re: justchillin]
justchillin Offline

Registered: 05/05/13
Posts: 491
Loc: cedar creek lake
Thanks for the responses. I just realized I said I did not replace the o-ring. What I meant was the rubber gasket that goes in the groove on the underside of the impeller housing. After initial draining when milky oil was found , I went out a couple of days later and took drain screw out again and the little bit of oil that came out was the color it is supposed to be. Could it possibly have just been a little condensation from the colder nights we had a few weeks ago ?

#12610105 - 02/04/18 12:51 PM Re: Water in lower unit question [Re: justchillin]
Dawson Hefner Offline
Extreme Angler

Registered: 09/10/09
Posts: 2965
Loc: Brownsboro, Tx
No it was water. There isn't enough air in your lower to be forming condensation in any meaningful amount unless it has a leak. It's possible it was one of your plug washers leaking by. Water pump parts do not have anything to do with water inside the gearcase, they are to maintain water pressure/fit not keep water out. There are lip seals meant to keep oil in and water out on the drive shaft and prop shaft.
Licensed guide Dawson Hefner
Guided rod and reel fishing trips for Alligator gar on the Trinity River
Hobo Outdoor Company Team Member


© 1998-2018 OUTDOOR SITES NETWORK all rights reserved USA and Worldwide