Mercruiser 120 Water in Oil low compression on cyl 2&3

[escapade]

I've got a Mercruiser 120 and the dip stick is a lil milky, however the big problem I have is on the oil cap the gunk on it has the consistancy of mayo see picture attached from my lil research could be a exhaust shutter?? which is possiblel because there is also a ticking sound on the top end near the rear of the engine close to the stern.


the other problem is cylinder 2&3 have approx 90 psi so that sounds to me like a head gasket between the two cylinders.

and one other small problem there is a strong exhaust smell at WOT however at idle it goes away, and with that i'm kinda lost any ideas on what I can do to help this engine??

 

[escapade]

Re: Mercruiser 120 Water in Oil low compression on cyl 2&3

If someone has an Idea that would be helpful, but I got to thinking more about it today, and I think that all these problems might be connected, exhaust valves along with the shutter, allowing water to enter the combustion chamber but the rings are sealing the majority of water from the bottom end (which could explain the excessive amount on the in the head compared to the oil pan) and if the exhaust valves are bad it could also be allowing exhaust to recriculate thru the breather and into the seating area of the boat, I'm going to take the valve cover off and check the spring pressure, worst case pull the head and rebuild it this winter.

If anyone else has some ideas I would apperciate them. Thanks

 

[Bondo]

Re: Mercruiser 120 Water in Oil low compression on cyl 2&3

Ayuh,... I don't think yer theory holds water,...

The Mayo on the filler cap, is condensate from the water in the oil,...
It gathers inside the valve cover, as the water vapor rises towards the vent, then condenses on the inside of the valve cover, being it's a large, relatively cool surface..
If it weren't bein' replenished from below, it'd steam off in no time at operatin' temps...

I'd Guess the compression problem with 2, & 3 is a failing head gasket,...
The water in the oil is probably a cracked block..

 

[wi4x4man]

Re: Mercruiser 120 Water in Oil low compression on cyl 2&3

I had seen the same thing once before, but it was on my truck years ago when I was in high school. Both heads had cracked in this case, and both rocker arm covers were loaded with that goop. It was apparently a design flaw in that engine (Ford, go figure) and was rather common. Cracked head = coolant getting into the crank case.

 

[escapade]

Re: Mercruiser 120 Water in Oil low compression on cyl 2&3

I guess trying to think postive did not work out so well.

I'm going to pressure test the block and if that is less then successful then I'm going to pull the head this weekend to see how bad things are.

 

[wi4x4man]

Re: Mercruiser 120 Water in Oil low compression on cyl 2&3

I tried to be positive with my most recent engine escapade too... Didn't work out for me either. Ended up pulling the head.

 

[rooferjoe]

Re: Mercruiser 120 Water in Oil low compression on cyl 2&3

Everything points to blown headgasket
Save time and energy pull the heads have them machined and serviced for crakes and warping and reinstall if this is to be a boat you intend to keep a while low compression and the cream in oil are signs that something is majorly wrong and cannot be sugar coated. Sorry to hear