New to boats and have a problem. Oil leak

[Bill Curtis]

I forgot to mention a cracked or rotted through exhaust manifold or riser /elbow can do it too, as can the gasket between the manifold and riser / elbow.

 

[mark reinwald]

Did compression test. Had

155-155-122-123

Next is to do a pressure test.

 

[dwna1a]

My bet is the riser/ manifold plus it’s gasket. Please keep us informed

 

[mark reinwald]

Now that you guys mentioned it and I looked up the manifold/riser. Looks like it has water jackets in it. When I got the boat water was dripping out and around the rubber connections on the riser part and I can see water lines from past drips. Would this be I sign of something? And when I remove the manifold am I looking for rust or condensation in there? Thanks. I’m new to all this boat stuff and your help has been awesome.

 

[dwna1a]

Look at the gaskets first, then the manifolds. Any idea when they were changed last?

 

[mark reinwald]

Look at the gaskets first, then the manifolds. Any idea when they were changed last?

No idea. Just got the boat.

 

[scoflaw]

Did compression test. Had

155-155-122-123

Next is to do a pressure test.

Numbers don't look good

 

[mark reinwald]

Numbers don't look good

Why, because they are inconsistent? As a whole I don’t think they are below spec but I read they should be no less then 20psi apart. Am I right with that?

 

[mark reinwald]

Why, because they are inconsistent? As a whole I don’t think they are below spec but I read they should be no less then 20psi apart. Am I right with that?

No leak down thought. They hold.

 

[mark reinwald]

If I’m gonna pull all the manifold and riser and everything does anyone have a place to get the right gaskets? I read that you don’t want to use cheap gaskets and Google just throws up a million options.

 

[scoflaw]

OEM is the way to go

 

[Nater Potater]

There's a few outlets out there that deal strictly with OEM parts. To avoid sounding like I'm promoting one over the other, just do a quick google search for Mercruiser. I learned the hard way when one of my shift cables let go while unloading my boat. Trying to get a twin back on the trailer with only one working outdrive is not worth the money I saved by going with aftermarket cables.

 

[mark reinwald]

I pulled the riser and found water sitting in the exhaust manifold. Checked the riser and it looks Okay. Ran some water though it and found no leaks. With my limited knowledge of this system I’m thinking the gasket for the manifold is leaking or the manifold is cracked and the water is leaking in though the water jacket. I can’t think of another way for water to sit in there. So I’m going to pull the manifold off and see what’s up.

 

[El Capitan]

love those 2.5L mercs.

 

[mark reinwald]

Ok just as a follow up I figured out what was wrong. The manifold water jacket is cracked. I’m replacing the manifold and hopefully I can get back out on the water by next weekend. Thanks for the help!