Impossible to Fix Westerbeke? 7.6BTD mocks all repair efforts!

[jimbunyard]

If you've got the raw water hose from the HE to the exhaust elbow off, just get any old hose that's close to the right size and attach it by any means necessary to the end of the existing hose and measure how much water comes out in a minute.

If it's about 1.5 - 3 gallons, the elbow is likely clogged, if it's much less, the problem is elsewhere.

Operating hours has nothing to do with it, even immaculate maintenance will not guarantee against a rust or scale or soot-clogged elbow; it could look fine on the inlet side and still be stopped up on the outlet side, regardless of how pristine the paint is...

Worked on at a 6KW westerbeke last year that looked and ran perfect -- until you kicked in the breaker. An internal generator ground fault smoked it; cost for just the stator was over 2 grand. The unit had 253 hours on it...but was about 12 years old. I'm guessing internal corrosion was the culprit, though mice have a bad habit of chewing on insulation.

[gonesail]

if the exhaust elbow is anything like the yanmar exhaust elbows .. this is the first place to look. it can be a pretty tough job too. sorry to hear yours is not removable

[Tspringer]

Given that I have verified that there is no blockage anywhere near the water injection fitting on the exhaust elbow it would seem that only a blockage where the exhaust elbow attaches to the giant exhaust hose is possible.

IF there was a blockage there that was enough to restrict water flow in the manner it seems to be restricted - then how are exhaust gasses getting out? If would seem back pressure would build and shut down the engine or otherwise blow out some other hose?

I can see how the water injection fitting could get blocked but I cannot see how soot or anything else could build up enough to block water flow at the large hose fitting and yet not cause huge back pressure issues with the exhaust. Just does not make any sense.

The generator installation on these boats is BAD.

I did also remove the cover plate to the impeller housing on the raw water pump. It DOES have a well defined round groove worn in the surface. I guess I can see how maybe this reduces flow? Does not seem like it would but what do I know?

So maybe I will reconnect it all and try running again to see if maybe that helps. Very few options remain that I am willing to embrace. Sucks that getting the exhaust elbow off is pretty much impossible without removing most of the cylinder head and manifold and then hoping a dremel tool can cut the strap at the elbow.

[Jesse]

As exhaust hoses age the inner lining separates from the stiffer part of the hose and causes a partial blockage and increases exhaust pressure which allows less water in. This causes higher temps in the exhaust hose causing more liner separation and less water passing through the entire system and the problem just keeps getting worse and worse, water will still pass through the exhaust, but not while the engine is running due to exhaust pressure. Raw water pumps produce high volume for their size but at low and variable pressure. I've had the same problem and thought I was going nuts, it was the exhaust hose

[Tspringer]

Originally Posted by Jesse

As exhaust hoses age the inner lining separates from the stiffer part of the hose and causes a partial blockage and increases exhaust pressure which allows less water in. This causes higher temps in the exhaust hose causing more liner separation and less water passing through the entire system and the problem just keeps getting worse and worse, water will still pass through the exhaust, but not while the engine is running due to exhaust pressure. Raw water pumps produce high volume for their size but at low and variable pressure. I've had the same problem and thought I was going nuts, it was the exhaust hose

I guess the question then is how close to the exhaust elbow will the main exhaust hose delamination be?

Removing the large exhaust hose from the exhaust elbow may not be possible without destructive efforts. I have messed with it for 2+ hours and see no way to remove that hose clamp - there is not even a means to get the cutting wheel on a dremel anywhere near it. IF it were only slightly turned in any other direction - no issue. It is perfectly set to be the maximum impossible. So if the large exhaust hose is bad as you think - I believe the issue will have to wait until I return to the States and then engage professional help to try and either remove the elbow or remove the entire generator.

[MicHughV]

after everything I've read here, still think the problem is at the impellor. If you can see groove marks on the the outer cover, that means there is no seal there....the impeller will rotate, but can't pump...that has to be a watertight fitting. The impeller will just swirl water around the inside

try this, put a heavy dollop of grease on that cover plate and the impeller blades....grease or vaseline, and re-install, without the gasket, get that plate as close to the impeller as you can, start genset...see if there is an improvement. Any improvements, will likely be short lived as the grease washes away but it will point to the problem..those impellers are designed to be water lubricated, but a bit of grease is not going to be a problem.

I've had a similar problem once, and that was the culprit...if you can't get a spare impeller plate, you can try sanding the groove out, I'd have to be there to see, but it can be done...

Those impellers can suck up a small bit of shell, etc and cause that

[Tspringer]

MicHughV ----> You got it right.

I "THINK" it is fixed. So far so good - generator is running normally, a good bit more water is spitting out the exhaust and so far after 10 minutes of running under load (battery charger - ice maker - water heater --- loaded up! ) the temp is steady at 170-175 which is where it normally stays.

After messing with the water inject fitting at the exhaust elbow and verifying that there was no blockage there - I decided to abandon anything more with the exhaust elbow as just not worth it. If the issue was down line from there - I'll pay someone else to fix it our just abandon having a generator. Haul it around as negative boat ballast to keep that super cool stern down look everyone wants.

BUT - I went back to the impeller cover. Inside once I got solvent on it to fully clean off the rubber residue it was clear there was a pronounced groove in the plate where the impeller would rub against it.

So I took the cover and flipped it over and sanded the face to perfectly clean bare metal. I then reinstalled it with the new face side down. Ran the generator and MUCH more water flowed out of the exhaust immediately. Im going to give it the old eyeball again right now....

Now the generator has been running under load for about 25 minutes. Temp is rock steady at 175 - oil pressure a nice 45psi - power getting pumped out just as it should. No funny noises, it certainly appears to be back to running normally.

So I am calling it fixed, ordering a new raw water pump rebuild kit and another spare cover plate and moving on to the next project.

Hot showers aboard tonight!

Yipeeeeeeeeeeeeeeeeee

Thanks for all the ideas and help!



Terry

[MicHughV]

yer welcome.....I see a cold Heinekin coming my way...

[SVTatia]

Originally Posted by Tspringer

MicHughV ----> You got it right.

I "THINK" it is fixed. So far so good - generator is running normally, a good bit more water is spitting out the exhaust and so far after 10 minutes of running under load (battery charger - ice maker - water heater --- loaded up! ) the temp is steady at 170-175 which is where it normally stays.

After messing with the water inject fitting at the exhaust elbow and verifying that there was no blockage there - I decided to abandon anything more with the exhaust elbow as just not worth it. If the issue was down line from there - I'll pay someone else to fix it our just abandon having a generator. Haul it around as negative boat ballast to keep that super cool stern down look everyone wants.

BUT - I went back to the impeller cover. Inside once I got solvent on it to fully clean off the rubber residue it was clear there was a pronounced groove in the plate where the impeller would rub against it.

So I took the cover and flipped it over and sanded the face to perfectly clean bare metal. I then reinstalled it with the new face side down. Ran the generator and MUCH more water flowed out of the exhaust immediately. Im going to give it the old eyeball again right now....

Now the generator has been running under load for about 25 minutes. Temp is rock steady at 175 - oil pressure a nice 45psi - power getting pumped out just as it should. No funny noises, it certainly appears to be back to running normally.

So I am calling it fixed, ordering a new raw water pump rebuild kit and another spare cover plate and moving on to the next project.

Hot showers aboard tonight!

Yipeeeeeeeeeeeeeeeeee

Thanks for all the ideas and help!



Terry

Great news.

[ttex]

Hey I would just like a sip of that beer as I mention the impeller too.

Glad you got it fixed bro I hate to have seen you sink your boat out of frustration.

[MicHughV]

I'll share.....

[rbk]

Originally Posted by Tspringer

MicHughV ----> You got it right.

I "THINK" it is fixed. So far so good - generator is running normally, a good bit more water is spitting out the exhaust and so far after 10 minutes of running under load (battery charger - ice maker - water heater --- loaded up! ) the temp is steady at 170-175 which is where it normally stays.

After messing with the water inject fitting at the exhaust elbow and verifying that there was no blockage there - I decided to abandon anything more with the exhaust elbow as just not worth it. If the issue was down line from there - I'll pay someone else to fix it our just abandon having a generator. Haul it around as negative boat ballast to keep that super cool stern down look everyone wants.

BUT - I went back to the impeller cover. Inside once I got solvent on it to fully clean off the rubber residue it was clear there was a pronounced groove in the plate where the impeller would rub against it.

So I took the cover and flipped it over and sanded the face to perfectly clean bare metal. I then reinstalled it with the new face side down. Ran the generator and MUCH more water flowed out of the exhaust immediately. Im going to give it the old eyeball again right now....

Now the generator has been running under load for about 25 minutes. Temp is rock steady at 175 - oil pressure a nice 45psi - power getting pumped out just as it should. No funny noises, it certainly appears to be back to running normally.

So I am calling it fixed, ordering a new raw water pump rebuild kit and another spare cover plate and moving on to the next project.

Hot showers aboard tonight!

Yipeeeeeeeeeeeeeeeeee

Thanks for all the ideas and help!



Terry

This is very common with outboards as well. Bit of sand or gravel can get stuck in the impeller housing and wears a grove in them. You can replace the impeller again and again but will overheat until you replace the housing.

[ShinyHappy]

I've been following this all day. Tspringer, I'm so glad you found the culprit. I needed the closure!

Great job to everyone for the ideas. I'd buy you all beers just for the feel-good story.

[Afrinus]

Oh No, MickhughV, now you've gone and ruin my plans by solving this mystery...I was going to offer Tspringer10$ to take that POS Bene off his hands to save him all the aggravation [emoji1787]

[Searles]

Do you have a plastic water lock muffler ,if so check that the heat hasn’t collapsed the unit inside ,or the hose from the exhaust elbow hasn’t delaminated and caused a flap which may block flow .⛵️⚓️