Chocolate coloured engine oil

[DJ111153]

I have a 2004 50 Hp EFI Mercury Outboard.
When my son did the winterizing last fall he said the engine oil looked like chocolate milk.
Would this be a problem with the water pump or head gasket.

 

[Chris1956]

Re: Chocolate coloured engine oil

4 cycle motor, right? If so, sounds like a leak from the cooling system into the crankcase. Could be a head gasket, cracked block or something else.

 

[MH Hawker]

Re: Chocolate coloured engine oil

Or it could be one of the several built in flaws of 4 strokes, that is not uncommon.

 

[DJ111153]

Re: Chocolate coloured engine oil

Or it could be one of the several built in flaws of 4 strokes, that is not uncommon.

What are the built in flaws are you refering to

 

[1nebel0]

Re: Chocolate coloured engine oil

water condersation turning into water in the oil...all over the next..very rare that it is a head gasket or cracked head though it does happen...more common thermostat stuck open letting the motor run to cold and not burning off the condensation forming in the motor...this is a big problem many people have and the marine shops see it all the time...The 4 stroke motors are not good in regards to trolling for hours...go figure..that is why you bought the 4 stroke beside the fuel economy...that water is diluting the oil and will wear out the motor prematurely...again search the net for some very good reads on this subject...