Water in oil - compression still good.

[deserttoad]

I have a 140 hp mercruiser that I just finished rebuilding the lower end (yesterday).<br /><br />Now I have water in the oil. I checked compression thinking I had a bad head gasket (changed that a couple years ago). Compression is about 125 on all cylinders except the #4, which is about 145. My number 3 and 4 plugs are wet.<br /><br />I've read several posts that say it could be my manifold.<br /><br />Since I really only run a half dozen times since the head gasket change, would it be worth a re torque on my head bolts?<br /><br />Please point me in the correct direction from here (to a mechanic perhaps?)<br /><br />Jim

 

[Trent]

Re: Water in oil - compression still good.

Pressure check the manafold and the riser. <br /><br />Poor mans way that works (75 percent of the time) is to pour gas (be careful) into the riser and manafold and look for leaks (after you remove them). If this boat is a saltwater boat and the manafold and riser is 4-6 years old go ahead and change them. Freshwater 10-15 years old; Change them.

 

[deserttoad]

Re: Water in oil - compression still good.

You mean just change the manifold and riser gaskets, or the complete units?<br /><br />I changed the gaskets when I had everything apart last time, if it had a gasket I changed it.<br /><br />Maybe I should retorque all those parts?<br /><br />This poor boat seems to be a losing battle. Perhaps I need a new army.

 

[Trent]

Re: Water in oil - compression still good.

I mean change the manafold and riser, and the gaskets. These are the main cause of water in the engine.

 

[Walter]

Re: Water in oil - compression still good.

I'm sure you've probably heard by now (I tend to dwell on my own tale of woe), but the port side manifold of my old 305 leaked water into the engine and trashed it. If I were you...that's the first thing I'd suspect...that and the riser.<br /><br />Again I find myself parroting Trent's advice...but at least this time I have first hand experience with what a leaking manifold can do. It's possible the problem is something else...but this should be your first line of attack.<br /><br />Walt

 

[deserttoad]

Re: Water in oil - compression still good.

Hmmm...Retorqued the manifold bolts, seems to have solved the problem (at least for today.<br /><br />But it looks like that unfixed the problem I fixed yesterday (lower unit oil is a little bit milky).<br /><br />Perhaps I should scuttle the ol gal....

 

[Walter]

Re: Water in oil - compression still good.

I can't see how loose manifold bolts could allow water into the engine. If the riser bolts were loose...then ok...I can understand that. Seems to me loose manifold bolts would only create an exhaust leak. Hmmmm... I think I'm gonna find a manual for your engine so I can get a better idea of what's what. Anyway...I sure hope your problem is resolved.<br /><br />As for milky outdrive fluid? Are you sure what you're seeing isn't residual from before? It doesn't take much contamination to change the gear lube color. You may want to consider changing the gear lube once more...maybe it will clear up. If it's obvious more water is being introduced into the gear lube...I'm afraid you're back to square one. One would have to assume that if the new water pump assembly was properly installed...the water would be coming in somewhere else. Are you still only running the engine on the garden hose, or have you had the boat in the water yet?

 

[Trent]

Re: Water in oil - compression still good.

Sorry but I still think you have a problem with water getting in the engine oil. (Hope Im wrong).

 

[deserttoad]

Re: Water in oil - compression still good.

Yeah, I imagine I do, but I'm still hoping.<br /><br />I ran it quite a bit out in the yard. Got it warmed up, checked the oil, checked the plugs for water. Did it over and over, everything seems okay.<br /><br />As for the lower unit, the oil seems a bit milky, but nothing like it was. It also still has the correct consistency for gear oil.<br /><br />I think I will run the boat for an hour or two and then check everything out again real good. This sound okay?<br /><br />Thanks,<br /><br />Jim

 

[Walter]

Re: Water in oil - compression still good.

I'll be keepin' my fingers crossed for ya!<br /><br />Let us know how she did.<br /><br />Walt

 

[deserttoad]

Re: Water in oil - compression still good.

Hi all!<br /><br /> Well we made the maiden voyage tuesday night and she ran like a champ! Had more power than before, ran smoother, and pulled people right out of the water. We skiid for about two hours then called it a night. I checked the engine oil - no water there. Checked the lower unit, still a bit milky. It was that way before we went out, and I don't think it got much worse, I will change the gear oil again and have another test flight, keeping my fingers crossed that the water pump is okay.<br /><br />Thanks to all that helped with the entire rebuild process!!!!!<br /><br />Jim