Genny shutting down

mratlndmrk

mratlndmrk

Well-Known Member
Mar 5, 2018
592
Newburyport, MA
Boat Info
2003 Sea Ray 380
Engines
Merc 8.1s
ZF 6.3 V Drives
Westerbeke 7.0 BCGB Genset
My westerbeke 7.0BCGB ran great the day of launch as we had no shore power I let it run for an hour or so to charge up the batteries. We changed the cap and rotor over the winter and it was actually running smoother than ever. Came back a couple of days later and since then it runs for 18-20 minutes and then shuts down. I can restart it by holding the "preheat" button but as soon as I release it it shuts down. Wait half hour and I can start it but the cycle repeats itself. First thought is overheating but we just replaced the water pump and it's pumping fine and the discharge water is cool to lukewarm at best. Looking for direction before calling the mechanic. Thanks in advance.
 
The preheat is effectively a sensor override. So… you have a bad sensor. Could be oil pressure, coolant temps, oil temp.
 
I’m going with a coolant temp sensor since it’s running until it warms up.
 
Thank you both....that was my thought as well but I wasn't sure. Is there a way to by-pass the sensors to figure out which one it is? I also should probably put a temp gun on it to make sure it is not in fact heating up too much.
 
Well before you start replacing/jumping sensors you may want to double check that 1.) it has coolant and 2.) it has oil :)

I think the check/replacement of sensors on our Westerbekes is pretty well documented if you do a search here. I've not done it myself but I'm sure my days are numbered...
 
Stee6043 said:
Well before you start replacing/jumping sensors you may want to double check that 1.) it has coolant and 2.) it has oil :)

I think the check/replacement of sensors on our Westerbekes is pretty well documented if you do a search here. I've not done it myself but I'm sure my days are numbered...
Click to expand...

Yes, coolant and oil are topped off. I find the search feature difficult to "tune" but I'll give it a go. Thanks.
 
mratlndmrk said:
Yes, coolant and oil are topped off. I find the search feature difficult to "tune" but I'll give it a go. Thanks.
Click to expand...

Yeah, it can be tricky.

One more thought - make sure your governor has oil. I assume a 2003 still has the mechanical governors...
 
I assume it's the sensors job to shut the engine down should it "sense" an issue? And in this case there does not appear to be an issue so it's probably a bad sensor?
 
mrsrobinson said:
I assume it's the sensors job to shut the engine down should it "sense" an issue? And in this case there does not appear to be an issue so it's probably a bad sensor?
Click to expand...

Assuming that full oil and coolant confirms you don't have an oil or cooling issue may not be the safest of assumptions :)
 
My question was more for me learning how all of this works should this ever happen to me. If I have a sensor telling me something is "wrong" that shuts down the genny, I confirm everything is ok, is it a bad sensor?
 
My Kohler is doing the same thing. Can almost use it as a timer for a 20 minute run time.

I've purchased all the sensors but haven't tackled the job yet.
 
mrsrobinson said:
My question was more for me learning how all of this works should this ever happen to me. If I have a sensor telling me something is "wrong" that shuts down the genny, I confirm everything is ok, is it a bad sensor?
Click to expand...

For sure. Sorry, I may have misread your post :) Good stuff.
 
My carbon monoxide sensor in the cabin was bad and my genny would not stay running. Just one more item to check?
 
Thanks all for the suggestions. I hope to get to it sometime this week.
 
I just wanted to share an update on this and where I am at. I ended up determining that it was definitely over-heating causing the shutdown. We replaced the exhaust elbow which was definitely burned out. Started it up and it still heated past 180 so we shut it down right away. I had bought a new thermostat too so we replaced that and ran a hose through the exhaust manifold to make sure nothing was clogging it up. Also pulled and cleaned the heat exchanger. Started it back up and watch the temp and it stabilized at 180. Ran it for 20 minutes with a load and watched the temp to be sure it stabilized and thought I was happy. A week later I was out and using it and it shut down again but this time after 40 minutes. When it shut down I shot it with the gun and it was below 180. Started it back up and it ran for another 45 minutes and same thing...shut down but temp was good everywhere. So although my heat issue is (or seems to be) resolved I'm back to square one on figuring out how to make this run non-stop.
 
I believe the sensors go to ground when they fault so unplugging all sensors and running the genny for 45 minutes then plugging in one sensor at a time while the genny is running would be a rudimentary method of finding the faulty sensor.
Just be sure all fluids are full and closely monitor the genny while running.
 
mratlndmrk said:
... I'm back to square one on figuring out how to make this run non-stop.
Click to expand...

When you cleaned the heat exchanger, did you also change the water pump impeller? Also you mentioned the exhaust elbow looked burnt, that sensor may be on it's way out as well.
 
SKybolt said:
When you cleaned the heat exchanger, did you also change the water pump impeller? Also you mentioned the exhaust elbow looked burnt, that sensor may be on it's way out as well.
Click to expand...
Yes new impeller and water pump actually. The exhaust elbow for this model is an "all in one". The sensor is built into the elbow which in thinking about it would be problematic if the sensor went. The elbow was $850ish. Last night I ran the generator for an hour and a half with no issues so who knows where I'm at. Thanks for all the suggestions.
 
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