# Water in 4 stroke crankcase



## lil goose (Oct 16, 2009)

I have a 15hp mercury 4 stroke and I was winterizing it when I pulled my dipstick the oil was like butterscotch colored. I did a little research and a couple of things seemed like it could be the cause. I did little fall brawling and they claim if the thermostat is stuck open and the cold water circulating will condense in the oil or possibly a head gasket. I only use the 15 hp to troll so what do you guys think. Any help would be greatly appreciated. Goose

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## SemperFi (Mar 10, 2014)

Head gasket would be the first place to look. need to do a leakdown test more than a compression test. Leakdown test consists of getting the engine to top dead center and holding it there/locking it there somehow, then using a leakdown tester to put air pressure into the engine. If the head gasket is blown into the sump then it will show up. 

That doesn't mean that there isn't an issue for you though, if it's blown just between the crankcase and the cooling system you can do leakdown and compression test and anything else you want to the cylinder and it will never show up. 
As it's not a sealed cooling system and the crankcase probably has a breather it's kind of hard to pressurize either to check for leaks. I doubt that you'll find any issues short of pulling the cylinder head off. My guess is it will be an hour or two at most if you have the tools and the manual, and head gaskets aren't all that much. If you take it to a shop it's probably a few hundred for the repair,


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## bountyhunter (Apr 28, 2004)

I just googled this [ 15hp mercury water in crankcase] lots of info . hope helps .


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## cincinnati (May 24, 2004)

Head gasket. Unless you have a crack in a water jacket, stuck (open) thermostat will only keep the engine from warming to normal operating temp.


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## lil goose (Oct 16, 2009)

bountyhunter said:


> I just googled this [ 15hp mercury water in crankcase] lots of info . hope helps .


Yeah I have that's why I am torn between the thermostat and head gasket. The motor ran great so you could imagine my surprise! Plus it was way over full so I don't know how much condensation that would take. Think I am going to start with the thermostat and go from there.

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## SemperFi (Mar 10, 2014)

Any condenation from T/S full open would evaporate from the heat of the motor in the oil!!!!


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## firemanmike2127 (Mar 17, 2013)

I haven't done any additional reading on this conition yet, but my instincts say if there's enough water in the oil to raise the level significantly that the head gasket is the likely culprit. Any idea how many hours of run time it took for this condition to appear ? Mike


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## lil goose (Oct 16, 2009)

firemanmike2127 said:


> I haven't done any additional reading on this conition yet, but my instincts say if there's enough water in the oil to raise the level significantly that the head gasket is the likely culprit. Any idea how many hours of run time it took for this condition to appear ? Mike


Yes the last 2 trips I took to E.72nd in late October. Probably 20 hrs of running time. Water temperature was 40 degrees. Like I said motor ran like a champ. That's why I was questioning if that much condensation could happen in 20 hrs? Thanks for your help!

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## Meerkat (Aug 10, 2008)

Hey Goose, did you by any chance run with the kicker down? Has not happened to me but the dealer I bought my Merc 9.9 kicker from told me never to run with the kicker down as it could force water through the cooling water intake and into the engine. Said this would negate warrantee. The other thing I try to do is if I have been trolling all day at idle speed (especially in cold water) then I will run the kicker at WOT for 5 minutes or so before I shut it down. Hope this helps. Joe


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## slimdaddy45 (Aug 27, 2007)

I would go with the head gasket 1st that much to raise the level do see it being condensation


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## lil goose (Oct 16, 2009)

Meerkat said:


> Hey Goose, did you by any chance run with the kicker down? Has not happened to me but the dealer I bought my Merc 9.9 kicker from told me never to run with the kicker down as it could force water through the cooling water intake and into the engine. Said this would negate warrantee. The other thing I try to do is if I have been trolling all day at idle speed (especially in cold water) then I will run the kicker at WOT for 5 minutes or so before I shut it down. Hope this helps. Joe
> 
> 
> Sent from my iPhone using Tapatalk


I don't believe I ran with I down but I didn't run it fast all I did was unhook the fuel line and ran it dry because I was done for the year. Think I am going to change the thermostat and run it and go from there. Head gasket doesn't look too terrible if need be. I just have a hard time thinking it was a gasket as great as it was running but that's why I am asking for help! Thanks buddy!!

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## MOBIL4 (Jan 30, 2011)

I have a 2013 mercury 9.9. Last year I had problems with it leaving film of fuel on the water and it took forever to warm up. Had to take it back three times last year for work. They also found water in the oil. They had to replace the thermostat and the fuel pump. Covered by warranty. Also needed to rebuild the carb. My next kicker will not be a mercury! I would change the thermostat. 


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## Meerkat (Aug 10, 2008)

lil goose said:


> I don't believe I ran with I down but I didn't run it fast all I did was unhook the fuel line and ran it dry because I was done for the year. Think I am going to change the thermostat and run it and go from there. Head gasket doesn't look too terrible if need be. I just have a hard time thinking it was a gasket as great as it was running but that's why I am asking for help! Thanks buddy!!
> 
> Sent from my XT1254 using Tapatalk


Head gasket could be leaking between water & oilways without losing compression and the motor would still run fine. I would agree with your suggested course of action. Thermostat & then head gasket. 


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## sherman51 (Apr 12, 2011)

sounds like a head gasket to me. to get enough condensation to raise the oil level is very unlikely. but it never hurts to start with the easy fix first. if its the thermostat stuck open you can see it as soon as you get to it. if its closed you can test it by putting it in a pan of water and turn on the heat. when it opens check the water temp. its not a big job to replace the head gasket. you can google it and see just how easy it is.

I just bought a boat with a 85 hp Johnson that runs great but has water coming out around the 1 and 3 cylinders. i'm guessing its a blown head gasket going to the outside but not into the cylinders. they gave me a price of 150.00 to 200.00 to replace the gasket if the head is good. its in the shop now getting the work done.
sherman


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## firemanmike2127 (Mar 17, 2013)

Sherman, I'd consider replacing both head gaskets if one has broken down enough that it has started to leak externally. It's very rare for a 90 or 100 cu. in. OMC V-4 to have a warped head. It is possible that any older O/B could have been subjected to overheating, but that particular cylinder head is a pretty stout casting. I've also seen a number of these older motors develop minor external water leaks on the exhaust cover as well. Mike


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## mmtchell (Jul 9, 2014)

I have a 2011 mercury 9.9 four stroke ,,, mine did the same thing ,, its the thermostat ,, mercury has went through some new part numbers because there thermostats were not hot enough the new part # is 8m0119207 71 degree Celsius thermostat which is 159.8 degree Fahrenheit ,, when running in cold cold water and the motor does not reach a hot temp that motor condensates fast ,,, mine was not closing all the way ,,, check it pull the 2 bolts ,, put it n a pan of water , heat it up check and see what temp it takes to do that ,,, then run it under cold water and see if it closes ,,, mine did not...... bingo big 4 stroke motors don't have this problem much because they are usually run wide open and get hot fast and that burns off the little condensation the had ,,, the little kicker motors are at idle most of the time so it takes time to reach operating temps


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## mmtchell (Jul 9, 2014)

And if the thermostat isn't operating right ,, it never gets hot enough to burn the moisture out of the crankcase breather, that go's to the top of the carb .... and if you smell the oil its real gasy too because the engine is running so cold that not all the gas is being burned in the combustion chamber and is leaking into the crankcase ...mine looked like sausage gravy without the sausage ,,,lol


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## rodbender (Nov 15, 2008)

This happened to me three weeks ago trolling in the cold water with my 2011 9.9 mercury four stroke. I had lots of water in the oil causing it to shoot out places I don’t know of and leaking in my garage. Change thermostat and gasket and have had it out three times and it is fine. 70 degree thermostat was $60. I would surely try this first. Good luck


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## mmtchell (Jul 9, 2014)

Yep. ..i first was hesitate on a 70 degree thermostat but its in Celsius which is almost 160 degrees. .Fahrenheit


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## fastwater (Apr 1, 2014)

mmtchell said:


> I have a 2011 mercury 9.9 four stroke ,,, mine did the same thing ,, its the thermostat ,, mercury has went through some new part numbers because there thermostats were not hot enough the new part # is 8m0119207 71 degree Celsius thermostat which is 159.8 degree Fahrenheit ,, when running in cold cold water and the motor does not reach a hot temp that motor condensates fast ,,, mine was not closing all the way ,,, check it pull the 2 bolts ,, put it n a pan of water , heat it up check and see what temp it takes to do that ,,, then run it under cold water and see if it closes ,,, mine did not...... bingo big 4 stroke motors don't have this problem much because they are usually run wide open and get hot fast and that burns off the little condensation the had ,,, the little kicker motors are at idle most of the time so it takes time to reach operating temps





mmtchell said:


> And if the thermostat isn't operating right ,, it never gets hot enough to burn the moisture out of the crankcase breather, that go's to the top of the carb .... and if you smell the oil its real gasy too because the engine is running so cold that not all the gas is being burned in the combustion chamber and is leaking into the crankcase ...mine looked like sausage gravy without the sausage ,,,lol





rodbender said:


> This happened to me three weeks ago trolling in the cold water with my 2011 9.9 mercury four stroke. I had lots of water in the oil causing it to shoot out places I don’t know of and leaking in my garage. Change thermostat and gasket and have had it out three times and it is fine. 70 degree thermostat was $60. I would surely try this first. Good luck





mmtchell said:


> Yep. ..i first was hesitate on a 70 degree thermostat but its in Celsius which is almost 160 degrees. .Fahrenheit


This thermostat business causing this is all very interesting.
Thanks for posting.


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## lil goose (Oct 16, 2009)

fastwater said:


> This thermostat business causing this is all very interesting.
> Thanks for posting.


Yeah that's what I was reading about these small motors "" making oil" Thanks guys I really appreciate your imput!!! Goose

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## Meerkat (Aug 10, 2008)

Hey Goose - let us know how you make out. I have one of those motors as do many of the guys on OGF. Thanks, Joe


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## sherman51 (Apr 12, 2011)

what all the guys are saying about the thermostat sounds like that could be the problem. start with a new thermostat and see if the problem goes away. then when running in cold water run the motor in neutral at a higher rpm for a few minutes to bring everything up to temp. start with simple 1st.
sherman


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## lil goose (Oct 16, 2009)

Meerkat said:


> Hey Goose - let us know how you make out. I have one of those motors as do many of the guys on OGF. Thanks, Joe


I sure will Joe. I am going to go ahead and replace the water pump and spark plugs as well. Got to get ready for next year!!! Thanks again everyone I appreciate the support!!

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## sherman51 (Apr 12, 2011)

lil goose said:


> I sure will Joe. I am going to go ahead and replace the water pump and spark plugs as well. Got to get ready for next year!!! Thanks again everyone I appreciate the support!!
> 
> Sent from my XT1254 using Tapatalk


hey goose its easy to support you as long as it doesn't cost us anything, LOL. you know i'm just kidding you. if there was any way I could help you i'd be more than happy to. good luck with the motor.
sherman


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## bajuski (Apr 9, 2004)

lil goose said:


> I sure will Joe. I am going to go ahead and replace the water pump and spark plugs as well. Got to get ready for next year!!! Thanks again everyone I appreciate the support!!
> 
> Sent from my XT1254 using Tapatalk



Take a look at your spark plugs when you pull them, if one plug is very clean, you have water in the combustion chamber.


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## Steimy (Jun 29, 2008)

My buddy just had the same issue. Thermostat was stuck open. Engine ran too cold causing condensation. He is a picture of the old and new one side by side. Merc changed them from the original one


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## FishIgo (Apr 21, 2011)

Had the same exact problem on my 2015 Mercury 40 HP four stroke it comes from running the motor in cold water and the thermostat is not closing to keep the temp up and the inside of the motor sweats ! mine was completely covered by warranty !


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## Meerkat (Aug 10, 2008)

Steimy said:


> My buddy just had the same issue. Thermostat was stuck open. Engine ran too cold causing condensation. He is a picture of the old and new one side by side. Merc changed them from the original one
> View attachment 286853


Hey Steimy - do you have a part number on the new style thermostat. Going to be doing maintenance over the next month or so & might as well replace the thermostat before I fill my crankcase with water


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## Steimy (Jun 29, 2008)

Checking with my friend. Stay tuned


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## Meerkat (Aug 10, 2008)

Thanks!


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## mmtchell (Jul 9, 2014)

8m0119207 that's the new part # quicksilver ,,,,, just did mine


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## Steimy (Jun 29, 2008)

mmtchell said:


> 8m0119207 that's the new part # quicksilver ,,,,, just did mine


Yes. That's the same order number my friend gave me.


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## Meerkat (Aug 10, 2008)

Cool! Thks guys. I will look it up. 


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## lil goose (Oct 16, 2009)

Well gave it a complete tune up with new thermostat, water pump, sparkplugs, fuel filter, oil filter and oil. It fired right up idled for about 10 min. Checked the oil and looked like butterscotch! So now it looks like I need a new head gasket! How much does it cost to get a new head gasket installed? Thanks

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## SemperFi (Mar 10, 2014)

I would say around $300. to $400. few hours labor and parts. Do it yourself it's winter and you have the time.


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## Meerkat (Aug 10, 2008)

If you can do a thermostat & waterpump you can do a head gasket. I have a torque wrench you can borrow if you need it.


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## bountyhunter (Apr 28, 2004)

I know you can do it, easier than a water pump... after all this you,ll be a pro at fixing motors.


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## lil goose (Oct 16, 2009)

Ok you guys have convinced me! Besides if I can replace the transom the head gasket should be a piece of cake!! LOL. Just hoping the head itself isn't cracked!!! I will keep you guys updated!! Goose

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## lil goose (Oct 16, 2009)

Well kiddos are finally done with basketball so I have a little time to get started on my head gasket replacement. Removed the old one today I was hoping to see something glaring but nothing obvious. On a good note nothing obvious on the head as well. I will give a report after the new replacement. Goose

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## sherman51 (Apr 12, 2011)

lil goose said:


> Well kiddos are finally done with basketball so I have a little time to get started on my head gasket replacement. Removed the old one today I was hoping to see something glaring but nothing obvious. On a good note nothing obvious on the head as well. I will give a report after the new replacement. Goose
> 
> Sent from my Moto Z3 Play using Tapatalk


you can always take the head to a machine shop and have it checked for cracks to be on the safe side. but I would say its just a gasket.
sherman


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## mmtchell (Jul 9, 2014)

just change the thermostat first ,,, its cheap and probably the problem ...


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## lil goose (Oct 16, 2009)

mmtchell said:


> just change the thermostat first ,,, its cheap and probably the problem ...


Already did still getting water in the oil.

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## lil goose (Oct 16, 2009)

Ok last one. Got the new head gasket installed and everything seems to be fine. Next test will be in April! LOL 

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