2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

[cich69]

Hello, I have a 2003 Rinker with a 6.2 MPI and Bravo 3 outdrive. Engine serial
#0M616167. Dry joint exhaust manifolds.

Last year the pickup on the outdrive got clogged by backing into mud in my channel. The temperature guage shot way up then quickly came back to normal. After shutting it off and waiting a little while it was hydrolocked and would not turn. Pulled plugs and shot all the water out (only had water on starboard cylinders) then put plugs back in started it and it ran great. went for a short ride and it ran great, came back and turned off engine and once again starboard cylinders filled with water and engine would not turn over.

Drained starboard exhaust manifold and removed elbow and riser, manifold was full of water. So, I took the manifold, riser, and elbow to my local machine shop to be tested. Was told there was a large crack in the exhaust manifold so I replaced the manifold and used all new gaskets for exhaust system. I also changed the impeller and checked the exhaust flappers on both sides, they looked like new.

That seemed to fix the problem, the boat ran great rest of last season (about 6 days of boating) and the first few times out this year. Then, it was hard to start one time and would not crank over the next time I tried. I pulled the spark plugs and once again there is water in the starboard cylinders. I cleared all the water out of the cylinders, ran the engine for a few minutes and did a compression test, the lowest reading on my gauge was 200, the highest was 210 so they were all very close. Replaced spark plugs with new plugs and went for a test drive, boat ran GREAT no running issues what so ever. Came back to the pier and pulled spark plugs, once again water on starboard plugs (at least three cylinders everytime I check). Next, I drained the manifold, removed the riser and elbow and again found a lot of water in the starboard manifold. So I swapped the port and starboard risers and elbows using new gaskets to see if the problem if the problem would follow the riser and manifold. No such luck, once again the starboard manifold was full of water after a test drive.

I have read the Mercruiser service bulletin on water intrusion and still don't have many other ideas. I took the new starboard side manifold off and plan to have it pressure tested tomorrow just in case there is an issue with the new manifold. I have watched the temperature gauge like a hawk since the original issue and it has never gone past 180 at full speed and usually idles about 140. I'm sure the manifolds and engine were completely drained last fall and then after draining everything I ran -100 marine antifreeze through everything just in case I missed any water.

Has anyone had problems with a new exhaust manifold being bad? Am I on the right track getting the new manifold tested?

Can anyone please give me any more ideas or things I should test? The boat is in one of Chicago's harbors and I live 1 hour away so I'm hoping to try everything I can next time I go there.

The boat runs AWESOME, idles great, jumps up on plane and is pretty quick for a 27' boat. The only problem is the water intrusion and I really wanted to get this issue fixed correctly. Please help!

 

[dingdongs]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

have you had starboard head off as there may be a cracked head or gasket has failed.water passages may also be full of mud which a lot of people never notice.a compression check should be high on the agenda and its not an expensive bit of kit.

 

[Bt Doctur]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

Had a new merc one start leaking within a week. quick test is remove the hoses to drain the manifolds, run engine briefly to dry the manifolds, remove the risers, put water into the lower hose SLOWLY untill you see it at the top of the manifold where the slots are.look inside manifold for wet spots or water droplets.Might take 1/2 hr or more to show.

 

[Pete104]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

Have you looked at the riser? Just for the heck of it, switch them side for side.

 

[cich69]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

Hello, Thank you all for the replies.

As stated in my original post I HAVE switched the risers and elbows from side to side (and used all new gaskets @$35 each) and the problem stayed on the starboard side.

I have checked the compression at least four times since this happened and there has been no change in compression. All cylinders are 200-210psi on my gauge. I did pull the the engine/manifold drain plugs and hoses and run the engine for 20-30 seconds until it looked like all mud was flushed from the engine..... I have not had the starboard head off yet and am planning to do that only as a last resort (which I might be getting near). But the thing I really don't understand is that the boat runs PERFECT. If there were a problem with a head or head gasket wouldn't I have some issue? Like: odd compression readings, or rough idle, loss of performance, etc...... The boat idles smooth as silk gets, right up on plane, has fast and smooth acceleration throughout the entire rpm range and never seems to miss a beat. It runs as well as it did when it was new, but always seems to have water in the starboard exhaust manifold and whichever cylinders have the exhaust valve open after running it up to planing speed.

Like I said "after changing the exhaust manifold the problem went away for the end of last year and the beginning of this year" then it mysteriously came back. The compression readings have not changed since last year.

 

[Philster]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

My bet, given what happened first, is that you possibly/briefly overheated the engine or created a hot spot, and as a result blew a head gasket and/or slightly warped a head.

Maybe someone can disagree, but it doesn't surprise me about the compression seeming good, and that she runs fine, ... yes, even with leaking at the head. I've seen it more than once. A hot spot, and not pure overheating readable at the gauge, would be possible and toast a part of the head gasket or head. Heck, based on your story, you are obligated to pursue this. Forget compression and how she runs. You'll lean on that and it is going to destroy you.

 

[Pete104]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

I totally agree. How about a leak down test?
By the way, Bond-o will never agree but to reuse a gasket in situation like this is OK. Just don't loose track of what you've done. I know they are expensive. Speaking of that, your not using riser "spacers" & have those dry-joint gaskets upside down, do ya? Just a thought.

 

[cich69]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

UPDATE: I plugged the bottom of the manifold where the water hose attaches and filled the water jacket on the manifold and found water pouring through a crack into my new manifold.

It doesn't look like a freeze crack as neither side is pushed out and like I said I completely drained everything then filled the engine and manifolds with -100 marine antifreeze. It looks like a flaw in the casting to me! Has anyone else dealt with this? Does Mercruiser warranty their parts?

Is there anything else that could have caused this new manifold to crack?

The temperature gauge always looks normal and if I feel both manifolds and risers while the engine is running they always feel the same temperature.

This boat only has 100 hours on it and has never been in salt water.

 

[Pete104]

Re: 2003 6.2 MPI water in cylinders. Tried almost everything, any more ideas?

Hopefully you have the receipts. They do warranty their parts, buying from a dealer always helps. Also, they have a consumer landline that takes calls & complaints.
The problem they are going to have, it's 1 manifold. Why did you buy 1 manifold? They don't know why!

Good luck! Please keep us posted.