water in pistons

Fellas, got a stupid question. Which gasket failure will most likely allow water to get into BOTH pistons?
getting milky oil on both plugs on the 9.9

My guess is the head gasket.

Do a compression check before diving in.
A milky substance in that area can also be as simple as an engine running too cold. Specially this time of year!

How long has it set since the last time it was run? If it has not run in a while there may have been some condensation inside the motor that is just getting sent to the cylinders. I have some trucks where I work that have a milky looking substance that builds up in the dipstick tubes because they are not run enough.

huntinfool said:

My guess is the head gasket.

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I was thinking that,but its both plugs and compression is good

Pappy said:

Do a compression check before diving in.
A milky substance in that area can also be as simple as an engine running too cold. Specially this time of year!

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Compression is 118 T & 120 B don't know if it has a T-stat or not. I've only ran it once since I picked it up. It ran like a champ,pushed the 14' approx 22 mph. Just not sure which gasket ,head , bypass or exhaust.

KMixson said:

How long has it set since the last time it was run? If it has not run in a while there may have been some condensation inside the motor that is just getting sent to the cylinders. I have some trucks where I work that have a milky looking substance that builds up in the dipstick tubes because they are not run enough.

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Last time it was run was about a month ago. Outside temp was 60 something. For whatever reason I pulled the plugs the other day and that's when I saw the milky oil ,so I left plugs out sprayed WD-40 in and spun motor with a batt drill to blow it all out.

Lots of problems with water in fuel these days. Could be just that. I would take it out and run it with a fresh tank of fuel before doing anything else. Next day check the plugs and see.

Let's face it, a 9.9 that goes 22mph runs fine in my book.

In any case, run it to flush through whatever is in there and see what happens. If the problem returns with good fuel, then start looking at gaskets.

Haven't had time to mess with it , working a lot of O/T (which is good) and up to my eye balls in a 25 I'm re-ringing.
Pretty sure it's either a 9.9 w/a 15 carb OR a 15 w/ a 9.9 hood, oh and the fuel was fresh from a high volume station,so I know it was good gas.

I would not use WD40 in any area that cannot be wiped / blown dry

It does not displace or remove water. It is hydroscopic and holds water in an emulsion.

Bring up an older thread. After a few life changing events the past 16 months and basically getting my life back in order, I started working on this problem again. Still haven't found where the water is coming from. I like this lil motor and don't want to trash it . I had the head resurfaced W/new gaskets, no luck , replaced the exhaust side water jacket gaskets, Added thermostat and gaskets

And am still getting water in the cylinders, Where the heck is it coming from ??


Compression is 120 T and 118 B IIRC.
Also fro those of you who need to remove the re-wind assy. , here's how I did mine

The coiled snake ready to bite !

make sure you dont have a cracked cylinder wall

I had a Chrysler 105 hp many years ago with one.

It ran fine, compression was fine but had the same problem. The crack was below the combustion chamber area

just another thing to check for

My omc15 sits on the river all summer. Temps go from 55f at night to 90f with 90% humidity during the day and with the sun beating down on it it surly gets hotter. One day/night temp cycle water vaporizes through out the motor during the day and condenses during the night inside the motor. If I pull a plug in the cool of the AM there is water on both plugs. If I wait until the heat of the afternoon there is no water. Every motor I've had in 40 years did this.

point is not all water is the same...

I hate to say it but you may have a crack. Cracks can be very hard to find sometimes depending on where they are located and how large they are. If you are sure the gaskets were installed correctly when you installed them the first time I would start to suspect a crack. You may have to have it magnafluxed to find the crack if it is cracked.

KMixson said:

I hate to say it but you may have a crack. Cracks can be very hard to find sometimes depending on where they are located and how large they are. If you are sure the gaskets were installed correctly when you installed them the first time I would start to suspect a crack. You may have to have it magnafluxed to find the crack if it is cracked.

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perchjerker said:

make sure you dont have a cracked cylinder wall
I had a Chrysler 105 hp many years ago with one.

It ran fine, compression was fine but had the same problem. The crack was below the combustion chamber area

just another thing to check for

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Much as I hate to say it yall might be right , though I didn't see any when I had the head off. The block isn't discolored as if it was ran too hot. Anyway, I'm going to put it in the river and run the snot out of it just to see how it runs. Let ya know how it goes. Thanks Fellas.