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  1. #1
    Join Date
    May 2011
    Location
    Colonial Heights, Va.
    Posts
    701

    Question Water in oil mystery

    Her is my delima. I started my 2012 90 HP Mercury with 80 hours 10 days ago for the first time this year. Been covered and carported since Oct. or Nov. I did not pull dipstick before starting. Motor started instantly and ran perfectly. I let it run at idle for about 15-20 minutes. Then I pulled dipstick revealing a water and oil mixture which overflowed out the dipstick hole. I immediately carried to Merc dealer to diagnose problem and hope that it was covered by warranty. Well, they have drained and flushed twice, running on muffs after each and then carried to river yesterday where they ran under load at 2500 rpm's for 20 minutes. So far no water has gotten into crankcase again. They plan one more trial today.

    My question to the great minds of the forum: Can anyone offer a reasonable explanation for the water in my crankcase other than someone thinking diluting the oil in my engine with water was a good idea?
    2012 Berkshire 230 CL LTD w/Tap Fins
    2012 90 HP Mercury on 6" Z-Lock Jack Plate and Stingray Stabilizer Fin
    2013 Load Rite Elite Trailer
    Located in beautiful Sunny, Central Virginia

  2. #2
    Join Date
    Jul 2006
    Location
    Raystown Country, PA
    Posts
    2,337

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    Wow, I hope the warranty takes care of the cost. I can't think of anything except some gasket failure that would let water in the crankcase, also hard to imagine that water could find it's way in from outside the engine.
    1992 Tracker Party barge 24 (new deck, carpet and interior, 2019)
    1996 Mercury 115 ELPTO
    1983 Sea Nymph FM171 Striper
    1985 Johnson 70 J70ELCO

    Raystown Country, PA

  3. #3
    Join Date
    Jul 2006
    Location
    Raystown Country, PA
    Posts
    2,337

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    An iboats thread on a 2006 model year Merc 90 4 stroke suggests a stuck thermostat, keeping the motor from reaching the operating range temperature and not cooking off the condense water. This man had a normal level before running and very high level after the mixture started getting stirred up.

    Maybe get the dealer to look at the computer history and see if it is getting into the proper operating range.

    They also mention a Mercury TSB on this issue for the 2006 motor.
    1992 Tracker Party barge 24 (new deck, carpet and interior, 2019)
    1996 Mercury 115 ELPTO
    1983 Sea Nymph FM171 Striper
    1985 Johnson 70 J70ELCO

    Raystown Country, PA

  4. #4
    Join Date
    Oct 2006
    Location
    Denver, North Carolina
    Posts
    3,467

    Default

    I've heard of condensation or motors "making oil" from not warming up and getting rid of the condensation but not coming out the dipstick. It's usually from idling too much or a lot of low rpm running.
    Carl & Suzi
    Denver,NC
    2007 Bennington 2275rl tri-toon
    150 Honda 15x15p Enertia
    Power assisted steering
    Beautiful Lake Norman
    Pleiku Vietnam 1971
    Agent Orange

  5. #5
    Join Date
    May 2013
    Location
    Edwardsville, IL
    Posts
    329

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    Are you sure all of it was water & not fuel? New engines that aren't fully broken in allow some fuel to leak past the rings. But at 80 hours, your engine ought to be broken in, provided it was filled with non-detergent oil to begin with. A compression test will verify that it's broken in. Boat engines tend to run cool, so it is possible that condensation had been building up from last year that wasn't burned off if you'd been babying the engine & not running it hard, as Cwag said. Running the engine at lower speeds every time out could allow water to accumulate in the crankcase. With 4 stroke boat engines it's a good idea to run them WOT for a few minutes every time out to get the engine good & warm so it'll burn the water out.

    4 stroke engines have their crankcases vented to atmosphere. Is there any way rain or snow could have gotten into the engine over the winter through the breather? (It doesn't sound likely, but it's a possibility) Does the engine have the correct prop (size & pitch)? I've heard of engines being over-propped & not making full rpms (power) & having this problem. As mentioned, a thermostat stuck open could also cause this.
    1994 Tracker Party Cruiser
    115 hp Merc, 2 stroke

  6. #6
    Join Date
    Jun 2004
    Posts
    6,226

    Default

    And keep the oil level toward the lower 1/3 of the hash marks on the dipstick when changing oil..
    Rick

    St. Louis/Lake of the Ozarks

  7. #7
    Join Date
    May 2011
    Location
    Colonial Heights, Va.
    Posts
    701

    Default

    Thanks for your input guys. The dealer worked closely with Mercury Marine in diagnosing the problem and they had no suggestions as to the cause of the water in the oil.

    Follow up question: Since water did end up in the oil in a fairly large quantity and the engine was run for approx 20 min, mostly at idle, and the water stayed in the crankcase for at least 4 additional days, what do you think is the likelihood that some permanent damage was done to the internal parts, ie bearings, of the engine. My concern is some pitting of the bearings decreasing the life of the engine.

    I actually had the boat sold and called the prospective buyer yesterday and took the boat off the market because of this concern.
    2012 Berkshire 230 CL LTD w/Tap Fins
    2012 90 HP Mercury on 6" Z-Lock Jack Plate and Stingray Stabilizer Fin
    2013 Load Rite Elite Trailer
    Located in beautiful Sunny, Central Virginia

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