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

[PeterBernard]

Thanks for the update. As you say, there's no need for high temp exhaust hose - in fact the wire reinforced PVC hose is exactly what we use.

In the interests of allowing for a potentially quick fix, it might be worth holding off on sending your pump away for checking until your new hose arrives - it really is such a quick and easy test (and as i say, exactly what the problem was on my identical genset with identical symptoms and identical remediation attempts), that it would be a shame to get the new hose and then be waiting for some indeterminate period to get the pump back (after which, if the problem IS solved, you won't necessarily know what fixed it if you've done both jobs).

[Tspringer]

Got the clear wire reinforced PVC hose installed from the thru-hull to the strainer and from the strainer to the water intake fitting on the generator housing. I also installed the rebuilt water pump">raw water pump that I received back.

Ran the generator - no change.

Not enough raw water flow, slow overheat and shut down.

Interestingly, I can see in the clear PVC hose coming from the strainer that there is air in the line. It is definitely NOT being filled with water, you can see the water cascading down into the hose from the strainer and just before the intake fitting at the generator housing there is a very clearly seen large air bubble at the top of the hose that is always there. So it seems the raw water pump is not pulling enough suction to fill the hose?

I also did have the strainer off and completely cleaned and tested it - there are no cracks or such to let air in under suction.

So anyhow I am right back to square #1.

Given that I have verified the heat exchanger is not blocked I guess the next thing has to be the water injection at the exhaust elbow. So I have to remove the exhaust elbow no matter what it takes. This is going to be a nightmare.

In the Westerbeke manual it does clearly state that the strainer should be self priming and thus installed below the waterline. Beneteau did NOT do this, the original strainer is above the waterline. But for 900hrs of running time this apparently worked fine.

Maybe a new strainer that can be mounted below the waterline?

Also still considering installing an electric raw water pump below the waterline near the thru-hull. If I could figure out from the Westerbeke wiring how to wire the pump such that it automatically came on when the generator began running I would do this for sure.

One the main reasons I chose this boat was that it had a diesel genset. Man was that dumb.

[PeterBernard]

Uggh - how frustrating!!!

Have you considered removing the strainer from the equation entirely by bypassing it temporarily, and running the hose directly from the inlet to the pump?

this would eliminate 2 potential sources of the problem - air getting in to the strainer causing those air bubbles, AND the strainer being mounted too high.

At least it's a relatively quick test - I'd be doing anything and everything I could prior to trying to remove that exhaust elbow.

[Tspringer]

Originally Posted by PeterBernard

Uggh - how frustrating!!!

Have you considered removing the strainer from the equation entirely by bypassing it temporarily, and running the hose directly from the inlet to the pump?

this would eliminate 2 potential sources of the problem - air getting in to the strainer causing those air bubbles, AND the strainer being mounted too high.

At least it's a relatively quick test - I'd be doing anything and everything I could prior to trying to remove that exhaust elbow.

I have been pouring over the electrical diagrams trying to figure out how to wire in an electric raw water pump that would automatically turn on when the generator began running and automatically turn off at shutdown. If I can figure this out, I will install a new below the waterline strainer and the electric pump.

I did remove the strainer, completely clean it, inspect it with magnifying glass AND tested it on the bench under suction. There are no strainer issues that could allow air into the system. This generator did run for 900 hours with this strainer setup.

The air bubbles in the line seem to indicate to me that there is just not enough suction from the pump. How this could be is beyond me.


I WOULD just hire a professional to tackle this but based on prior experience this would certainly result in several Thousand $$$$ of expense while most certainly NOT being guaranteed of any positive result at all. I once paid over $4000 in repairs on a diesel Yanmar engine including for a new turbo all from a very respectable, long time in business diesel specialist company and in the end the issue was a broken ring that I discovered - they never found that. Diesel mechanics and accountants -- both make more $$$ if they are incompetent rather than skilled.

[Kerryf]

I have had issues with larger rubber impellors failing due to too much pressure. In my case it was blocked water injection elbows. The failed impellors looked 100% fine but the bronze bushing part of the impellor had become detached from the rubber and would spin inside it when the going got tough. It would spin fine with the impellor cover off but as soon as it had to pump water it would go into "neutral".

[PeterBernard]

I understand that you've bench tested the strainer, but still think it's worth bypassing it completely. As I say, it's an easy test, and the benefits are two-fold:

1. The bench test is not the same as when it's in situ. I had a similar issue on my genset when I didn't have the lid of the strainer screwed on tight enough. The extra bit of torque I applied was enough to seal the o-ring just that little bit more, and suddenly I had water where before there was none - these systems are VERY sensitive.

2. You mentioned that you were concerned about the strainer being above the water line. By bypassing it, you can eliminate this variable.

As I say, this is a 5 minute test, and in accordance with KISS principles, is surely worth doing before going to the time and expense of installing an additional electric pump?

[hpeer]

NO NOT SQUARE ONE. YOU ARE NEARLY THERE.

You should NOT have air in there.

You have an AIR LEAK between the strainer outlet and through hull.

Where is the question.

PeterBernard above gives great advice.

[Tspringer]

Originally Posted by PeterBernard

I understand that you've bench tested the strainer, but still think it's worth bypassing it completely. As I say, it's an easy test, and the benefits are two-fold:

1. The bench test is not the same as when it's in situ. I had a similar issue on my genset when I didn't have the lid of the strainer screwed on tight enough. The extra bit of torque I applied was enough to seal the o-ring just that little bit more, and suddenly I had water where before there was none - these systems are VERY sensitive.

2. You mentioned that you were concerned about the strainer being above the water line. By bypassing it, you can eliminate this variable.

As I say, this is a 5 minute test, and in accordance with KISS principles, is surely worth doing before going to the time and expense of installing an additional electric pump?

Makes sense - much appreciated.

I am going to run the clear raw water line that currently goes from the thru-hull to the strainer instead directly to the raw water pump intake. This will eliminate both the strainer and the intake fitting at the generator box from the circuit. Downside is that here in Brunswick GA the water is VERY murky and full of all sorts of marine life and such. So can't run it for very long.

I'll post back after this test is done.

[Tspringer]

Originally Posted by PeterBernard

I understand that you've bench tested the strainer, but still think it's worth bypassing it completely. As I say, it's an easy test, and the benefits are two-fold:

1. The bench test is not the same as when it's in situ. I had a similar issue on my genset when I didn't have the lid of the strainer screwed on tight enough. The extra bit of torque I applied was enough to seal the o-ring just that little bit more, and suddenly I had water where before there was none - these systems are VERY sensitive.

2. You mentioned that you were concerned about the strainer being above the water line. By bypassing it, you can eliminate this variable.

As I say, this is a 5 minute test, and in accordance with KISS principles, is surely worth doing before going to the time and expense of installing an additional electric pump?

PROGRESS!

So with the raw water feed line run directly from the thru-hull to the raw water intake at the pump the water floods out the exhaust.

So the issue is clearly either the strainer or the fittings at the generator box for water input.

So I think the thing to do would be to install a new heavy duty bronze strainer below the waterline and also completely replace the water intake fittings at the generator box.

At least I know for sure now that the issue is NOT the exhaust elbow!

[Tspringer]

More testing...

I ran the raw water hose from the thru-hull back to the strainer and then the outline line from the strainer straight to the raw water pump -- skipping the fittings at the generator housing and the hose from the fitting to the raw water pump.

Water still floods out the exhaust as it should. BUT - I can see a few bubbles here and there in the line from the strainer to the pump. The amount of water flowing from the exhaust seems the same as when the strainer was not in the loop, but there are without question some bubbles in the line.

So that brings me back to thinking on installing a new Groco ARG-1000 bronze strainer below the waterline and eliminate the strainer and mounting location that Beneteau decided upon.

[Tspringer]

On and on it goes...

I replaced the bronze fittings at the generator box where the hose from the strainer connects, then the hose inside the genset from this fitting to the raw water pump and then very short hose between the pump and the heat exchanger. I filled the strainer with water to prime and ran the genset again.

Now I see no bubbles in the feed hose, water gushes out the exhaust as it should.

But the pump itself is leaking now. Drip drip drip.... seems to be from the center section of the pump but hard to tell.

So after all this its $500 for a new pump. No way am I going to waste more time and money on rebuilt pumps. When the brand new one arrives, maybe I will play around with this one on the bench to maybe have as a spare. Unless these rebuilt pumps are 100% bench tested to pump water correctly and not leak, I would not install one.

[Searles]

An on going saga ,fitting a magnetic drive electric pump after the s w filter may help ,wire into the oil pleasure switch is the simple way ,also check your engine pump has the correct cam as these can alter water volume at same rpm .⛵️⚓️

[Tspringer]

CRUSHING DISAPPOINTMENT.


So the brand new $500 raw water pump arrived. I installed it, quadruple checked all of the hose connections and strainer and then ran the genset.

BINGO --- Water GUSHES out the exhaust, no leaks anywhere in the system and power generation is perfect. So I turn on the A/C and some other stuff to run the generator under load with a plan to do so for an hour in order to see if any issues continued.

The guage at the cockpit showed a maximum temp of 175F. Water gushed from the exhaust consistently. Oil pressure shows about 40psi as normal when at temp. Everything looks great, nothing wrong at all that can be seen.

BOOM - the generator automatically shuts down after about 20 minutes of running.

I have no idea why.

Again - the water now flows out of the exhaust gangbusters and the temp guage for engine water temp shows 175F. Oil pressure shows normal. Power is being generated as normal. But after 20 minutes it just shuts down. Why? I have no idea. Can't even think of where to start.


Anyone have any ideas on where to even start trying to figure this out? We had planned on getting out the marina to head south in 2 weeks to start the cruising season. Now, I don't know what we will do. It seems maybe we just need to plan and do as if we just did not have a genset because this PoS is just that.



Terry

[Nicholson58]

Terry,
Sure sounds like there is a temperature switch somewhere. This would drop the fuel solenoid on high temperature. These things do fail. Look for one in the electric drawings. It could be in line with a relay or possibly directly in series with the fuel solenoid coil. I have one on me 4-cyl 12.5 kw Westerbeke generator. It has saved my bacon a few times.

I have also had thermostat failures. I eventually put all of my used and new spares in a sauce pan and raised the temperature to see when they were open. The electronic cooking thermometer was perfect for this. I threw out two including the installed trouble maker. Main engine overheat is now history. Mark and rank the spares if you do this. In a pinch you can remove the thermostat entirely and run cold. I also bought a couple 160 thermostats.

Sounds like your water pump was leaking air. I had that too. A nice mechanic in Antigua rebuilt it, seals & bearings for less than $100 US. Don’t toss the old pump!

The boat came with spare heat exchangers. Swapping in the spare made a difference even though there appeared to be nothing wrong. Had the old one boiled and rebuilt.

Buck up. You are almost there and nearly an expert.

[CaptNemoO2]

Full disclosure, didn't read the whole thread...

Some ideas to check:
-Is the thermostat working properly?

-Is the temp sender still working properly? Check if the coolant is actually the temperature the gauge is reading.

-A quick look online, I was able to find the service manual for this genset. There is a temperature switch, exhaust temp switch, and an oil pressure switch all tied into the stop solenoid to shut down the engine. Have you checked that these are all working properly? They are wired in series, and it looks like they are probably normally closed switches (solenoid is energized when genset is running). When the engine shuts down, check which of those has an open circuit. That will tell you the condition causing the shut down (engine overheat, exhaust overheat, low oil pressure) or if there is a faulty switch.

-How is the generator head cooled? Air or water? Is there a temp switch on the generator head?