Chocolate coloured engine oil (4 Stroke EFI 50hp outboard)

When my son did the winterizing of my boat he noted that the oil was chocolate a color. I know it is water getting in some where. The boat was running good the last time I had it out on the water. Has anyone else had this problem and resolved it?
2004 4 Stroke EFI 50hp outboard

 

You mean the gearcase or the engine ?

 

Sorry all Engine oil

 

Usually a head gasket problem when there is water in the engine oil.

 

My experience with engines (I saw one once), if water is getting into the oil, it creates a greyish to milky colour.

If the oil is dark chocolate it is being cooked.

I recommend a compression test.

Poida

 

If water has mixed with oil it will contain some cafe au lait colored froth or mousse.

Dino

 

Nothing will tell you where the water is getting in except tearing the engine apart.
Sorry.

Head gasket typically unless the block or head is cracked.
But drain and replace the oil to see if it repeats its self.
I had someone (newbie) put water in the wrong filler hole once. Nothing actually wrong with the engine.

 

The most common cause is a failed riser, then the manifold or the gasket in between. Taking off the riser and inspecting them is only 8 bolts and two gaskets.

 

Certainly worth doing a compression test, which would mainly be a test of the gasket.

 

Not really. A bad gasket between the oil and water passages is not connected to the cylinder.

 

Probably not, but an easy check that might as well be done.

 

Dinoa

I must remember not to go to your coffee shop.

Especially not eat your chocolate brownies.

Poida

 

Gonzo

You must have different head gaskets where you live.

However the reason for a compression test is to see if the firing of the cylinder is not going past the rings into the crankcase. But if the head gasket is shot would indicate pressure is being lost through the gasket which on engines I have seen seal the cylinder between the crankcase and the head.

Poida

 

The gasket may seal around the cylinder/head area but not between the water/oil passages.

 

First remove the spark plugs and crank the engine by hand and feel and listen, if she doesn't turn smoothly or if you hear any grinding or crunching, then don't try to start or you could cause more damage. If you did over winter her with water sitting in a cylinder and that cylinder is rusty then you don't want that junk circulating and grinding in the engine.

Has the oil level rose? Otherwise the cause of the oil color is probably not water or at least not much. (Or there must be also oil leakage which can be seen on the engine or on the water surface, or there must be also a lot of oil usage which can be seen as a lot of bluish smoke which stinks. Post#1 says the boat was running good the last time she out on the water, so I assume there was no oil leakage visable and not a lot of bluish smoke.)

If the head gasket has a water leak to a cylinder then this water will partially evaporate during combustion which causes steam in the exhaust gases what can be seen as "white smoke", but I'm not sure if this exhaust steam doesn't immediately condensate underwater. I know the "steam smoke" from cars with water leakage to a cylinder through a leak head gasket. Post#1 says the boat was running good the last time she out on the water, so I assume there was no steam in the exhaust gases and no "white smoke" visible (again I'm not sure if the exhaust steam doesn't immediately condensate underwater). If there's no "white smoke" there's probably no water leakage into a cylinder through a leak head gasket. Still possible for the head gasket to leak on a water/oil passage as Gonzo says.

Check the thermostat, if it remains open when cold than the engine will remain to cold, this causes a lot of condensation in the engine and thus water in the oil.

This link is about inboards but it's a good read anyway . . . :idea:

Good luck !