Water in oil

[jonwebb]

I have 1986 Renken with a 4.3L OMC with a Cobra outdrive.The boat runs great in my yard with the hose hooked up to it.I have had the boat in the lake 2 times since I bought it.Both times the oil had water mix with it.Its like as soon as the outdrive is submerged the oil mixes with water in the crankcase.When I pull the spark plugs they are perfect so not in the cylinders.The boat remains running great even with the oil mixing with water.In my yard with the water hose hooked up to it and clean oil in it you can run it as long as you want to and it does not mix at all. Any Suguestions?????

 

[Knightgang]

Re: Water in oil

There has been alot of talk on this issue lately with several different I/O owners. One found out he had a slight crack in a cylinder on a rebuilt engine. Another had a blown head gasket (they do not always dump water in the cylinder) and others supect that the valve in the risers is bad and causing water th seep back into the cylinder via an open exhaust valve and then settling in the crankcase...

Or, another issue could be that you have a brown or cracked intake gasket. There are many reasons that can cause water in the oil, you just have to track down which one it really is...

How long have you had the boat? Did you do a sea trial before you bought it? Did you check fluids before and after the run? Also, is the oil level in the crankcase rising with the water in it, if so how much? Is it a significant rise? That could help define where the water is comming from and has serious an issue it really is...

 

[bruceb58]

Re: Water in oil

If you are getting just a little water in your oil, it is possible it is a bad riser/manifold or its joint. The water will not enter the oil until you turn the motor off and the water will enter a cylinder through an open exhaust valve and then seep by the rings. This will cause a non noticeable rise in your oil level. You may find that your engine can get hydro locked if this happens and enough water is entering the cylinder. It doesn't take much water to make it look milky.

If your oil level is rising considerably, you more than likely have a cracked block or water passage somewhere. You will need to pressurize your cooling passages to determine if this is the case.

 

[bruceb58]

Re: Water in oil

and others supect that the valve in the risers is bad and causing water th seep back into the cylinder via an open exhaust valve and then settling in the crankcase.

No valves in risers.

 

[Bondo]

Re: Water in oil

I have had the boat in the lake 2 times since I bought it. the oil mixes with water in the crankcase.
Any Suguestions?????

Ayuh,... My Guess is, you bought a boat with a Freeze Cracked block...
Whether it's Cracked, or just a gasket failure,...
A Cooling System Pressure Test might tell you exactly where to Look...