Water leak

[Bruce53]

I have a water leak in my 1986 140 SS 195 as seen when I roll the engine without the plugs installed. #2 cylinder shoots out water vapor from the plug hole. All other cylinders are fine. Valves are operating correctly. I suspect a head crack and am taking the head to the shop. If the head shows no crack, what are the odds that there could be a crack in the cylinder wall? The engine has been rebored twice. Thanks for any help on this thing.....
Bruce

 

[WillyBWright]

Re: Water leak

Welcome to iboats.

I assume that you are talking about a 140Hp inline-6 outboard. There is no head. It's just a water jacket cover. They like to leak after an overheat. Removing the old gasket is the hardest part. You have to basically chisel them off. Other than that it's a pretty straightforward job and about all you need is a plug wrench, 7/16 wrench, scraper(s), and a gasket.

However, if the water is coming from inside the cylinder, it's cracked. No fixing that.

 

[Bruce53]

Re: Water leak

Should have been more clear: it is a Stingray 4 cylinder Mercruiser sterndrive. Today the shop did a mag and pressure test on the head and certified the head (very reputable shop). They blame the maniford which, I concur, is shot. But, since #1 and #2 intakes are together (no separation) in the manifold, I can't see how #2 could spray out a mist and not #1 also -- and it doesn't. Sooo, I am getting a new manifold tomorrow and will reassemble and give it another shot. My fear: the head may be a lot newer than the block and, after 20 years of saltwater cooling and at least two rebores, the cylinder wall may have a crack or pinhole or rust-through, although I have never heard of a cylinder wall leak. We'll see.....

 

[j_martin]

Re: Water leak

The first thing to break would be the head, or head gasket.

The head gasket will leak into only one cylinder. Also, depending on where the leak is, the intake manifold gasket could leak into only one port.

Do you have any water in the oil?

John

 

[Bruce53]

Re: Water leak

Hi Guys... Shaved head and new head gasket and I have done a number of head torques so I am confident there. Haven't checked the oil yet but I would guess there will be some and I will have to clean that out. New manifold goes on tomorrow. Shop says that is my problem but I am not convinced. Sure would hate to have to tear the thing down again. Anyone know what the torque should be on the manifold? -- I was guessing.
Last thought: I used RTV sealer on the head bolts, not a non-hardening permatex II as I should have. Would that have led to a water channel so early in the rebuild?

 

[Bruce53]

Re: Water leak

Watch out for Sierra boat-engine parts. I selected a header from the catalog with all correct data and a picture to boot. Got a header with the same part number on the box but not the same header as shown in their picture and, of course, it didn't fit. Made in China. Another delay...

 

[emckelvy]

Re: Water leak

Shouldn't this thread be moved OUT of the outboards section and into I/O's??

 

[Bruce53]

Re: Water leak

Disaster: I idled for ten minutes and then ran the engine at the pier in forward gear at about 1200 rpm. The temperature climbed after the thermostat opened and slowly ran over 220 degrees showing a steam-stream so I shut down. When I let it cool for thirty minutes, I couldn't get it started! What a mess. I have the battery on charge now and am thinking.
I don't have a heat exchanger setup, tho I plan to get one someday because I am in the ocean (Monterey Bay). Anyhow, the connections without the exchanger are pretty simple and I don't see a problem there. I overhauled a sports-car engine once and immediately burned a piston because I had an airlock in the head. Could that be my problem and how do I vent the head to get a full head of water to start with? Also how do I go about testing or checking the output of the outdrive pump? Finally, no, I didn't dismantle the outdrive. The boat never had an overheating problem before the re-build so it has to be something I screwed up in the assembly. Oil pressure was about 40 psi but it fell to 30 when it overheated. Guess that would be expected. I will check the oil for water. The battery is back in the boat and I plan to put it back in the water on Monday. There is no fresh water flush where I keep it at this time. Last item: I have about two quarts of 10-40 and two quarts of 30 weight oil in the engine. The book says that is a no-no but I can't see why it would matter. Do you? Sure do appreciate your suggestions, guys. I don't have any pro help around here so I am relying on the Clymer shop manual which I find lacking in some spots....

 

[Bruce53]

Re: Water leak

Shouldn't this thread be moved OUT of the outboards section and into I/O's??

Hi Chief.... Yes, it should be. The Navy didn't teach me how to operate this dam thing......

 

[Bruce53]

Re: Water leak

I put the boat back in and it did ok for three minutes and then overheated. I let it cool a bit and then disconnected the pipe from the outdrive at the thermostat house to see how much pressure the outdrive pump would give me. Ola! No water at all even at 1200 rpm. I dropped the lower gear housing and will put in a new impeller tomorrow. Hope that is all that is wrong. Once I get the cooling system straighten out I suspect I will be able to work on the carb.

The first compression test a few weeks ago showed a general even 120 in all four. Now, after maybe a total of thirty minutes of running, the first three cylinders show an even 150 but #4 shows 140 exactly. I put a shot of oil in the plug hole and the pressure went to 145. I guess I am loosing 5 pounds to the rings. How much of a problem would that 10 pounds give me in general operations? And have I damaged something in #4 with the several overheatings?

 

[Bruce53]

Re: Water leak

Transferred this thread to the Mercruiser section where it should have been to start with. Sorry 'bout that.....