WESTERBEKE 4.5 BCGB SHUTS DOWN

thbouro

Member
Jan 6, 2011
98
VA Beach, VA
Boat Info
310 Sundancer 2001, Raymarine A65, Lowrance HDS 9 Gen 2 Touch, Raymarine Evolution EV-200 A/P
Engines
350 Mercruiser Mag MPI V-Drive
Engine shuts down after about 12 min of steady operation under no load. No apparent rpm increase at the moment of the shut down. Any thoughts?
 
Have you tried to hit the bypass/preheat button when it starts to shut down? If so, does that keep it running?

Does it immediately refire?

I had a similar issue with a 4.5 but it was a longer run than 12 minutes. Turned out to be a shorting wire in my main loom. Huge PITA and half a season to find and have repaired...
 
Have you tried to hit the bypass/preheat button when it starts to shut down? If so, does that keep it running?

Does it immediately refire?

I had a similar issue with a 4.5 but it was a longer run than 12 minutes. Turned out to be a shorting wire in my main loom. Huge PITA and half a season to find and have repaired...

Thanks for the reply Stee6043, this is a very good point, unfortunately I didn't check it! I suppose that, if I had depressed the bypass/preheat button and the engine refires, it was an indication of faulty safety switch (Oil pres, exhaust temp, water temp)! Is that right?

What I noticed is that, at the moment of the rpm reduction and engine shut down, the blue light on the gen start/run button (on the DC Main Distribution Panel) blinked momentarily. Does this help?

Could you please be more specific concerning the shorting wire you were experienced? Where was that?
 
Thanks for the reply Stee6043, this is a very good point, unfortunately I didn't check it! I suppose that, if I had depressed the bypass/preheat button and the engine refires, it was an indication of faulty safety switch (Oil pres, exhaust temp, water temp)! Is that right?

What I noticed is that, at the moment of the rpm reduction and engine shut down, the blue light on the gen start/run button (on the DC Main Distribution Panel) blinked momentarily. Does this help?

Could you please be more specific concerning the shorting wire you were experienced? Where was that?

If you can prevent it from fully quitting with the bypass switch - it's a sensor assuming it's not actually hot, has good water flow and has oil :). Then you just need to find which sensor needs to be replaced. Pretty straight forward.

The short was in one of the main wires. I can't tell you which wire but it was a pretty consistent period of run time when the short would occur (I assume heat related) and the gen would quit. It would not refire reliably after this. I nearly lost a liver dealing with this issue. Root cause (I assume) was that the main loom for the gen set on my 340 was in a place very likely to be stepped on when servicing things. It was a tightly wrapped set of 10+ wires that made it very hard to diagnose or even know to look there. I doubt this is a common failure mode, for the record.
 
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If you can prevent it from fully quitting with the bypass switch - it's a sensor assuming it's not actually hot, has good water flow and has oil :). Then you just need to find which sensor needs to be replaced. Pretty straight forward.

The short was in one of the main wires. I can't tell you which wire but it was a pretty consistent period of run time when the short would occur (I assume heat related) and the gen would quit. It would not refire reliably after this. I nearly lost a liver dealing with this issue. Root cause (I assume) was that the main loom for the gen set on my 340 was in a place very likely to be stepped on when servicing things. It was a tightly wrapped set of 10+ wires that made it very hard to diagnose or even know to look there. I doubt this is a common failure mode, for the record.
Thank you for your fruitful info! Hope it's not the wiring issue! Is there any specific way to check the sensors, other than replacing each sensor with a new one?
 
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Thank you for your fruitful info! Hope it's not the wiring issue! Is there any specific way to check the sensors, other than replacing each sensor with a new one?

If you can confirm it's a sensor you should be able to use a multi-meter to find which one is faulty or opening/closing when it's not supposed to. There are likely some very specific threads on this here on the forum. This comes up pretty regularly.
 
It's also possible to use a jumper wire with alligator clips to bridge the two connections for the sensor.

Capture.JPG
 
I’m dealing with the same exact problem. I’m getting clips tomorrow so I can jump all the sensors and eliminate which one it is. I’ve also though possibly a momentary switch. I’m still at wits end, I hope we both can conquer this little dilemma..
 
Can someone please pass a note of aggression to fix this switch related sensor stopping 4.5 Westerbeke from shutting down when releasing the preheat and start button.. if I hold it in it will run..
 
next to the switches located on the genny there is a fuse holder(small black knob). Check this fuse before anything else.
 
The fuse is brand new one and without the fuse it wouldn’t get power, however maybe vibration, but it starts just when I release the switch it shuts down.. I’m trying all new switches tomorrow then jumping all the sensors.. It’s crazy
 
The fuse is brand new one and without the fuse it wouldn’t get power, however maybe vibration, but it starts just when I release the switch it shuts down.. I’m trying all new switches tomorrow then jumping all the sensors.. It’s crazy
Could you please post the results?
 
Posting a result from months of chasing a problem where my 7.0 BCG would run fine for an hour, or for 3 hours, or for 5 minutes, and then shutdown.
Long story short, it turned out the be the fuel shutoff solenoid. Not the connection, not the voltage, but physically the solenoid. I purchased a new one from CARP, and installed it. It worked even worse, in that it wouldn't run a minute.
After exhausting every other possiblity, I concluded that I had received a bad new part. CARP was good about replacing it, but the factory was backordered for nearly 8 weeks. Oh, bad batch of shutoff solenoids? I inquired. No answer.
Finally received the new replacement, installed it, and the genset has run like new ever since.
 

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