2003 mercruiser 3.0 water ontop of cylinders

[longswl]

Newbie here, been reading a lot of posts finding several similar but none exact so thought I would give it a shot.

Getting water on top of what appears to be all 4 cylinders, mostly #4. Going back a little, noticed water in the oil after weekend fishing trip and then noticed water in #4 cylinder. Changed the oil and filter (a couple times) turned the motor over to get all the water out of the cylinders. Fresh oil and filter started the boat up (fired right up) and let run for a few minutes. checked the oil and it still looked pretty good, tried to restart and it would not fire up, pulled the plugs and water. so now I try something, after blowing the water out again I run the muffs on the out drive and turn over the motor with no plugs in and within seconds I start blowing water out of cylinder #4.

forgot to mention that after I had removed the water the first go around I ran a compression check 130, 125, 130, 140

Was about to start pulling the exhaust to see if I have an issue here but would it even make it that far if all I am doing is turning it over with no plugs in and muffs filling it up?

appreciate the feedback!!

 

[Bt Doctur]

elbow failure dropping water into #4

 

[achris]

15 years old... Still the original exhaust elbow?

Chris..........

 

[longswl]

just getting ready to break it loose (exhaust elbow) and yes I would guess it is original. Bolts snapped off and around the backside there is definite signs of rust.

 

[longswl]

Just got the riser elbow off and looking down into the exhaust manifold it is full of water (or at least to where it would seep into the exhaust valves)

Is this just a matter of replacing exhaust gaskets or much more?

 

[Bt Doctur]

need to find out where the water came from. elbow/ manifold/ head/ block

 

[longswl]

What would be the first thing I should do without taking anything further apart? I know that by removing things you can mess your self up down the road and really want to avoid that!!

Thanks again for all your help!!

 

[Scott Danforth]

My guess...youre in salt water, the exhaust manifold and elbow joint has long since rusted.

How long have you had rust streaks on the outside of the elbow/manifold?

Post up some pics

 

[longswl]

I literally just bought this boat two weeks ago, I did all the things I knew to look for, checking the oil, looking under the fill cap for signs of white gunk and compression check. So I really don't know how long it has been rusted, but the elbow itself actually appears to be in good shape. I will take some pics and post here shortly.

 

[longswl]

Having a problem uploading the photos

 

[achris]

Pictures need to be PNG format, and less than 2k in size.

 

[longswl]

Pictures need to be PNG format, and less than 2k in size.

Oh boy, now you are talking a different language

 

[longswl]

So far everything I am reading is telling me to remove the exhaust manifold and see if you can detect where the water is getting in? Does this sound right?

 

[Bt Doctur]

You already remove the elbow and found water. Test the elbow
Remove the hose from the front of the manifold , dry the inside of the manifold , and fill manifold to the top , Any leakage will be evident
If no leakage, drain and remove manifold, install muffs and water and crank. If water out the plug hole or exaust post , remove head and inspect

 

[longswl]

Thank you!!

I pulled the exhaust manifold and tested, it holds solid but does appear that it was leaking at the riser elbow. But I will do as you suggest and put the muffs on and crank it over and check the plug hole and exhaust post.

Thanks again, you all truly help!!

 

[longswl]

No water coming out of the plug holes (not sure what you meant by exhaust post) but I ran the water for a good 10 minutes and cranked it over several times with no signs of water anywhere. Everything looks like it points to the riser gasket and the elbow looking like the water side being fairly plugged up.

Now my question is does this really make sense? I got water in the engine while idling, I would think even at idle it would force any water out the exhaust?

I am thinking about getting some gaskets and reinstall everything (replace elbow later after more tests) clean the elbow out and test run and see if I get any water. If everything looks good after 1/2 hour of running replace the elbow and gasket and get her out on the pond.

Thoughts??

 

[adruid]

If you get to the point of taking off the manifold, you will be able to see signs water in the cylinders and ports. This is from water leaking at the manifold/elbow junction. I've had this problem before. The surfaces that meet on these to parts MUST be totally flat before they are put back together. (I opted for a new manifold and elbow. Check for flatness even when new.) Use the best gasket you can find and check the torque on the mating bolts fairly regularly. You'll likely have to take the head off and have it cleaned up and valves re-seated at the least.

 

[achris]

"The best gasket you can find" is the genuine Merc one, it's a graphite impregnated composite. Any other gasket will leak.

Chris.......

 

[longswl]

Thank you

I definitely see where water had gotten into the exhaust side of the head, the surfaces actually look pretty good both on the cylinder and exhaust faces (based on only using straight edge), the elbow is a bit rough but not too bad and is really flat all the way around also. fingers crossed I got lucky and caught it quick enough!!

 

[wahlejim]

When you reinstall make sure that the hose clamps on the robber boot between the elbow and y-pipe are tight on both the elbow and the y-pipe. I had the y-pipe clamps loosen up on me when I did mine and caused the same problem. The system needs to be sealed all the way through the transom.