It Usually Means Something

[WanderingStar]

I tend to vary between hoping that a potential problem is really no problem at all, and fearing the worst. This year my exhaust has been showing a little smoke or steam. I rationalized that it was just vapor on cool days, or hot exhaust. I also feared that it was oil or fuel and that my 43 year old engine needed serious repair. Last week as I put her at the winter dock, my boat neighbor observed the steam (now seen even at idle). He also asked about the small amount of water coming out. Sure enough, I realized that as the steam increased, the water, which used to splash out, now only sprinkled. The thermostat remained normal. A joint examination of the engine room revealed no obvious answer, but there was water on the sole. A leak for sure. Today I removed the leaking hose, resolved to examine the rest of the sytem and relace any suspect hoses.
Just sayin'.

[Lake Superior Sailor]

Sounds like you might want to check the water impeller, low flow & steam & all.--Dale

[ereiss]

what kind of engine? Fresh water cooled?

[centaursailor]

Originally Posted by Lake Superior Sailor

Sounds like you might want to check the water impeller, low flow & steam & all.--Dale

I,d have a look at this first, and the drive belt.
Safe sailing

[svHyLyte]

Originally Posted by WanderingStar

I tend to vary between hoping that a potential problem is really no problem at all, and fearing the worst. This year my exhaust has been showing a little smoke or steam. I rationalized that it was just vapor on cool days, or hot exhaust. I also feared that it was oil or fuel and that my 43 year old engine needed serious repair. Last week as I put her at the winter dock, my boat neighbor observed the steam (now seen even at idle). He also asked about the small amount of water coming out. Sure enough, I realized that as the steam increased, the water, which used to splash out, now only sprinkled. The thermostat remained normal. A joint examination of the engine room revealed no obvious answer, but there was water on the sole. A leak for sure. Today I removed the leaking hose, resolved to examine the rest of the sytem and relace any suspect hoses.
Just sayin'.

Based upon your description, to me it sounds as if the raw-water feed line is obstructed although it could be the heat exchanger or the water injection nozzle. In any case, I find it hard to understand why the engine would not have over heated. Perhaps you were just lucky. If the impeller has shed a vane or two, while it might still pump enough water to cool the engine, if the vanes were sitting in the raw-water feed line, obstructing the flow, you could have the symptoms you describe--including the leakage as the obstructed flow would result in pressure build-up in hoses that are not normally so pressurized.

If, like many 4-107's, your raw-water pump feeds the heat exchanger through an anti-siphon valve; and, if your impeller is shy a vane or two, they, or their parts, may be obstructing the valve or have gotten into the input side of the heat exchanger. Your task will be to recover all of the parts although back-flushing is not particularly difficult.

For what it's worth, I have found that replacing the raw-water impeller at the earlier of 100 hours or 12 months a wise precaution.

FWIW...

[WanderingStar]

Thank you all for your advice. I put a new impeller in this spring, though it might have been flawed or I might have made a mistake on the install. I will check the flow after replacing the hose. I also changed the zincs at that time. I'll check there too. The pressure in the leaking hose was high enough to shoot a stream to the overhead.

[CalebD]

Take a look at Maine Sail's photos of a HX that had not been serviced in a while: Westerbeke / Universal Marine Heat Exchanger Photo Gallery by Compass Marine at pbase.com
It is actually not such a bad job to disconnect and remove the HX for cleaning/servicing. I did it on a friends boat and it was not so bad nor was the HX obstructed with old zincs like the MS photos show.
How easy to do this depends on how easy it is to get to your HX as installed.
You will figure this out.

[svHyLyte]

Originally Posted by WanderingStar

Thank you all for your advice. I put a new impeller in this spring, though it might have been flawed or I might have made a mistake on the install. I will check the flow after replacing the hose. I also changed the zincs at that time. I'll check there too. The pressure in the leaking hose was high enough to shoot a stream to the overhead.

If the pressure was that great with a new impeller, I suspect that an obstructed injection port in the mixing elbow may be the villain. Perhaps debris blown out of the heat exchanger bundle or otherwise. Heat exchangers are not that difficult to clean out but a pain in the neck. The injection nozzle on the mixing elbow? Well, changing the elbow may be the fastest--and surely cleanest--solution.

FWIW...

[WanderingStar]

Shouldn't be the heat ex, I took it apart in spring, it was all clear. The leaking line went to the exhaust elbow, I'm suspicious there. In fact I wonder if the new zinc may have been enough longer than the old to partially block the flow. I hope to check today.

[svHyLyte]

Originally Posted by WanderingStar

Shouldn't be the heat ex, I took it apart in spring, it was all clear. The leaking line went to the exhaust elbow, I'm suspicious there. In fact I wonder if the new zinc may have been enough longer than the old to partially block the flow. I hope to check today.

Given everything you've said and done, and the absence of water flow through the exhaust, it would seem that the injection nozzle is obstructed. We have a friend that experienced a similar problem with his engine during a cruise to Key West last year. When he finally limped in and his engine cooled, we pulled the injection nozzle to discover all but a tiny hole left due to carbon/salt build-up. An hour with a Drummel tool followed by several hours of soaking in a solution of fresh water and Saltaway cleared it enough to allow him to make it back to Tampa Bay without difficulty. He probably could have continued to use the nozzle for awhile but elected to replace it once he got home. We have found that one of the best sources for parts is Transatlantic Diesel ("TAD") although I'm sure there is no shortage of other suppliers in the northeast.

Good Luck!

PS: If you elect to clear the nozzle with a Drummel tool, wear eye protection!