Water in oil in crankcase

Lfriedman

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Feb 22, 2014
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10
Just discovered when I checked the oil in my 90 hp mercury 4 stroke it was milky. Motor recently serviced after sitting for a couple of years. Took it out a couple of weeks ago after serviced and ran fine. Ran too good to be a blown head gasket or could it still run ok with a blown gasket. Any other help before I take it to the shop. Want to drain the bad oil and cache filter, how do I get all the water oil out other than changing oil a couple of times
Thanks for the help
 

Bondo

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Re: Water in oil in crankcase

Just discovered when I checked the oil in my 90 hp mercury 4 stroke it was milky. Motor recently serviced after sitting for a couple of years. Took it out a couple of weeks ago after serviced and ran fine. Ran too good to be a blown head gasket or could it still run ok with a blown gasket. Any other help before I take it to the shop. Want to drain the bad oil and cache filter, how do I get all the water oil out other than changing oil a couple of times
Thanks for the help

Ayuh,... Welcome Aboard,... Just Drain it,....

If there's a tiny bit of water left, it'll steam off the 1st time ya run it up to temp,...
 

bilge rat jim

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Jun 28, 2012
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Re: Water in oil in crankcase

Listen to Bondo - Change your oil and filter once. Multiple oil changes to remove water only serves 1 purpose- it makes the oil companies a little richer.

"But," you ask wisely- "where did the water come from?" A head gasket that has blown between the waterways and the oil passages will allow water into the crankcase without affecting compression or performance.
 

Lfriedman

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Feb 22, 2014
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Re: Water in oil in crankcase.

Re: Water in oil in crankcase.

Ayuh,... Welcome Aboard,... Just Drain it,....

If there's a tiny bit of water left, it'll steam off the 1st time ya run it up to temp,...

There is definetly water getting into the crankcase . The level mark is about 1-1.5" above full mark on dip stick. Any other place water could coming from other than head gasket. Just had new water pump installed and boat was sitting for a couple of years. Thanks lee
 

Lfriedman

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Feb 22, 2014
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Re: Water in oil in crankcase

It is milky color which tells me it is water not fuel.it has less 3 hrs on a new oil change. Should I drain enough out to get to the right level . Or completely drain and start with new oil and filter.
 

Faztbullet

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Mar 2, 2008
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15,935
Re: Water in oil in crankcase

With water being so cool the crankcase will condensate and cause water in oil. Change the oil and filter and after running let engine idle for 5 minutes to cool it down slowly .
 

Lfriedman

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Feb 22, 2014
Messages
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Re: Water in oil in crankcase

Would condensate cause the +- extra quart of water/oil I am seeing on the dip stick level. The boat has been sitting for a couple of years prior to putting in the water last week . Had complete tune up done carps completely reworked and all oils changed.reading other posts on this issue looks like the grommet on the water tube thru the oil sump.
 

bilge rat jim

Petty Officer 1st Class
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Jun 28, 2012
Messages
330
Re: Water in oil in crankcase

It is milky color which tells me it is water not fuel.it has less 3 hrs on a new oil change. Should I drain enough out to get to the right level . Or completely drain and start with new oil and filter.

Lets start by finding out where the water is coming from- have you done a compression test?
 

Lfriedman

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Feb 22, 2014
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Re: Water in oil in crankcase

Taking to local shop tomorrow I'll letth do compression test
Thanks will post results
Lee
 

1nebel0

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Nov 28, 2005
Messages
512
Re: Water in oil in crankcase

This is a very common problem with 4 strokes..many articles written about "making oil"... I had a 115 that had water in the oil and it did turn out to be a head gasket but this is the exception rather than the rule...Most people think right away head gasket when there is water in the oil..The short story version is that these motors run to cold and many times has a stuck open therm that keeps the engine running too cold and the moisture condenses and turns into water.. A lot of water to your point.. A leak down test will show up the head gasket problem and not a compression test on this motor....My bet is either the thermostat or the motor is used to much for idling...Google this and you will see many great reads that back up my few sentences.. I need to go to bed...let us know....
 

Lfriedman

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Joined
Feb 22, 2014
Messages
10
Re: Water in oil in crankcase

The mercury gods are not with me, local shop said hole it water jacket block, time to re power .. Now the question is 4 stroke or back to 2 stroke. Any comments out there
 

1nebel0

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Nov 28, 2005
Messages
512
Re: Water in oil in crankcase

Get a second opinion....Faztbullet your thoughts??? Hard to believe unless it is nothing but a salty dog!
 

Lfriedman

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Joined
Feb 22, 2014
Messages
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Re: Water in oil in crankcase

Yes barely a hairline in exhaust top port, signs of water in cylinder head top two on leak down test
 
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