Water in the oil

TracyMS

Cadet
Joined
Dec 18, 2010
Messages
7
My 2006 Merc 115HP 4 stroke had a lot of water in the motor oil when I drained it today. It has been running just fine. How could this be? How bad a problem am I looking at?
 

Jeep Man

Commander
Joined
Oct 17, 2008
Messages
2,803
Re: Water in the oil

You are probably the victim of the phenomenon known as "Making Oil". I do not profess to know the absolute cause of this but I will try to enlighten you a bit. Many 4 stroke motors that are not run full out for much of their use and are used at low throttle for trolling, leisurely cruising etc. can have this happen. Primarily the oil does not heat up enough and you end up with condensation, which collects over time. This is the nature of the beast, not a defect. From what I understand, running it differently can alleviate the issue. Hopefully someone more versed than I will chime in with a better explanation.
Other than this, the other possibility is a damaged head gasket which will require an immediate repair. It would not be advisable to run the motor with a damaged gasket.
 
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