Outboard oil emulsified?

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Slowtack

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My Johnson (Suzuki) 2.5hp 4 stroke engine oil now looks like Baileys cream. First noticed this last week and changed the oil twice since. I am puzzled that the oil level is not rising due to the water ingress so i guess the amount of water involved is very small. The oil I drained off into a bottle has not segregated since - still looks like Baileys. The cooling water flow was always very poor until I had the impeller replaced and the thermostat removed recently. The cooling water is now flowing properly, the engine runs very cold though. I am wondering if low temperature operation could affect the oil appearance/consistency somehow even if there was no water ingress? I seem to recall reading something like this about the oil in diesels cooled directly by seawater?
 
If it was a car engine I would say head gasket straight away. I don't have any experience with four stroke outboards but that would still be my first guess, especially if the engine has had previous cooling problems.
 
It could be a head gasket leak, but you say there is no increase in oil... If the thermostat has been removed, the engine will be running cold and will not reach the running temperature required to get rid of condensation in the sump. I would replace the thermostat as a first step and maybe change the head gasket if you have the engine on the bench anyway.

Many outboards have a hard life, being used infrequently and for short duration. Another reason why a two-stroke is better as a small outboard!

Rob.
 
It does not take much water to make the oil into "milk shake"

By all means check the thermostat. It should just start to open at the specified temperature which should be marked on it. If its been removed replace it. That could be the cause of the trouble.

It's a problem that requires urgent investigation because if it is sea water ingress you don't want to be lubricating the engine with oil containing salt water!
 
I always check the simple things 1st, did you use a new gasket when you changes the oil? Reuse of a gasket will let in enough to emulsify the oil. Did you fully drain the old oil and how long did you let it drain for, I always leave mine overnight to make sure I've got rid of the old stuff and any water in it.
 
I emptied the old oil refilled, ran for about a half hour, drained out again overnight and refilled.Still no oil volume increase. Interesting point about sump condensation. Will replace stat and oil again as first step before assuming head gasket is the issue. You dont need to change the gasket when doing an oil change. There is an O ring on the filler/drain cap. Thanks all.
 
Slowtack said:
I emptied the old oil refilled, ran for about a half hour, drained out again overnight and refilled.Still no oil volume increase. Interesting point about sump condensation. Will replace stat and oil again as first step before assuming head gasket is the issue. You dont need to change the gasket when doing an oil change. There is an O ring on the filler/drain cap. Thanks all.
Click to expand...

The o rings on the plug and breather holes were the gaskets I was talking about.
 
Landlockedpirate I think we are at cross purposes. My problem is with the engine head oil not the lower gear unit.
 
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