Westerbeke 7.6 BTD random shut downs

dtfeld

Water Contrails
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Jun 5, 2016
5,519
Milton, GA
Boat Info
410 Sundancer
2001
12" Axiom and 9" Axiom+ MFD
Engines
Cat 3126 V-Drives
Generator has been running flawlessly for the last couple years. However, I serviced all the fuel filters earlier in the year and since then, I've had random shut downs. Sometime she runs for 20 minutes, sometime s 3-4 hours, then she dies. Starts right back up, wash, rinse, repeat, I do not suspect any of the safety shutdown switches.

I first assumed air was getting into the system due to having just serviced the fuel system. I went back and checked all the fuel filters/caps, fittings etc. I thought I had it solved.

NOPE!!

Now I suspect something in the stop/emergency stop circuit. I'm thinking about replacing all the toggle switches on the generator itself. I've suspected a problem with the Emergency Stop toggle for a while now. My thinking is all the vibration on those switches along with time has compromised the switch(s).

Thoughts?
 
I had that exact same problem on my 400DA's 7.6BTD. It ended up being the toggle switch in the generator's electrical terminal box. The vibration over the years broke the wire right at the switch potting. Insulation was intact so visually you'd never know. Just by accident I had my fingers in that box while it was running and it shut down; from there and wiggling wires I was able to find the culprit. Then another similar issue cropped up where the 12V circuit power wire in that connector by the Monoplex (10 Gauge wire) cooked the pin and socket in the connector and created an intermittent condition. That was easier to find due to the connector was discolored and a bit melted.
 
didnt get parts ordered, but looks like a standard SPST switch. I'm going to get one from the Home Despot and try that to see if things improve.

I'm sure that diesel vibration takes its toll after a while...
 
We had a similar issue, sometimes it would run all day, sometime 15 minutes. Turned out to be the heat exchanger. Looked like plenty of water, but I guess not enough. Replaced and it was fixed.
 
The emergency shut down switch was the problem. As soon as I touched/wiggled it, I saw a little blue spark. Swapped out a new switch, and I’m back in business.

I couldn’t get the exact switch, but got one close enough that I think I’ve eliminated the random shut downs at least for the 4th week-end.
 
Hold the presses!!!

Generator ran great for about 5-6 hours then back to random shut down. Back to about shutting down about 15-20 minutes apart, maybe up to an hour.

seems electrical, but could also be a little air in the fuel???? I may check the small cartridge filter is installed correctly.
 
Still random shut down. It got to be one of the shutdown sensors, or the blower control module as it will also shut the generator down. Maybe a bad/loose connection or bad relay, or something in the fuel run solenoid.

I noticed that the Sea Ray Systems Monitor display showed “Generator Shutdown”, but I’m afraid this is only a symptom of the shutdown as I think it only monitors oil pressure. The alarm lags the shutdown by a second or two, so I don’t think any useful intel from the systems monitor.

im going to have to start jumpering sensors to see if one is bad. Any bets on what this is
 
Hey Dave - Did you pull this connector (circled in green) apart and look closely at it?
7.6BTD schematic.jpg
 
Had a same issue, two different times, 1st time a loose wire in crimp fitting on a sensor, second time the return fuel line had deteriorated on the inside and was letting air in the system
 
"im going to have to start jumpering sensors to see if one is bad. Any bets on what this is"
1. The one that is the most inaccessible
OR
2. The one that is the most expensive.
 
"im going to have to start jumpering sensors to see if one is bad. Any bets on what this is"
1. The one that is the most inaccessible
AND
2. The one that is the most expensive.

fixed it for you.
 
Had a same issue, two different times, 1st time a loose wire in crimp fitting on a sensor, second time the return fuel line had deteriorated on the inside and was letting air in the system
Return line or feed line? I wouldn’t think the return line wouldn’t have any effect.
 
I didn’t think the return would cause a problem, but it did, the hose had like a plastic liner that was separating, letting air in an causing it to shutdown
 
I had similar. Unplugging/replugging the harness connection fixed it for me.

Did the plug have a zip tie on it to hold the two halves together?
 
Looks like a bad exhaust temperature sensor. I jumped it out of the circuit and the genny ran happily all day. When I went to tighten up the screw terminals, one fell off into my hand, looks like the body was cracking due to age and vibration.

That temp sensor had never been mounted correctly with only 1 screw holding it in place. Additionally, it is mounted on the back side of the exhaust elbow making it very difficult to access, so I removed the entire exhaust elbow, and am going to rebuild it, and mount that sensor on the front of the elbow so future repairs are easier. Parts ordered.

One last issue.

When I separated the exhaust manifold from the exhaust elbow, the manifold sealing surface looks to be pitted/corroded. When I reinstall the new gasket, is there a gasketing material that would be acceptable to add to insure a good seal? I temporarily reinstalled the old gasket and it seems to be sealing fine, but...
upload_2022-7-17_11-5-42.png
 
Looks like a bad exhaust temperature sensor. I jumped it out of the circuit and the genny ran happily all day. When I went to tighten up the screw terminals, one fell off into my hand, looks like the body was cracking due to age and vibration.

That temp sensor had never been mounted correctly with only 1 screw holding it in place. Additionally, it is mounted on the back side of the exhaust elbow making it very difficult to access, so I removed the entire exhaust elbow, and am going to rebuild it, and mount that sensor on the front of the elbow so future repairs are easier. Parts ordered.

One last issue.

When I separated the exhaust manifold from the exhaust elbow, the manifold sealing surface looks to be pitted/corroded. When I reinstall the new gasket, is there a gasketing material that would be acceptable to add to insure a good seal? I temporarily reinstalled the old gasket and it seems to be sealing fine, but...
View attachment 130617
This one is their "Max Temp", a thin coating would be my suggestion.
https://www.autozone.com/sealants-g...CqLtY5V1-ZmxS-MJYJhoCDE8QAvD_BwE&gclsrc=aw.ds
 
Maybe some of this...
upload_2022-7-17_11-20-44.png
 

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