Genny shutting down

You need to find which sensor is shutting the engine down and why, oil pres., coolant temp, or exhaust temp.

When it shuts down can you re-start immediately? If not try jumping one sensor at a time to see which one is the issue. Might help narrow that down.
 
I'm not convinced on the sensor failed theory.... Two typical areas are the relays and switches. Relays can heat soak and cease working then come back when they cool and same with toggle switches that are worn and not making good electrical contact. This is a gasoline genny so a bit out of my AOE..... Still many similarities with the diesel units..
 
mratlndmrk said:
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.
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You need to monitor your frequency and voltage. There is an overspeed sensor which will shut down the genset seemingly random times. Get one of these
AC_SL1000_.jpg
 
ttmott said:
I'm not convinced on the sensor failed theory.... Two typical areas are the relays and switches. Relays can heat soak and cease working then come back when they cool and same with toggle switches that are worn and not making good electrical contact. This is a gasoline genny so a bit out of my AOE..... Still many similarities with the diesel units..
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Agree about the sensors but for a different reason. The design of the sensors is to shut down the generator if one of them trips. Nine times out of ten the sensor is not the problem.....simply the messenger.

In this case, I would look from the intake port to the raw water pump. A Westerbeke is sensitive to having enough water flow. A blockage (or air leak) in the intake port, hose to strainer, strainer and the hose to the raw water pump can create enough restriction that it trips the exhaust heat sensor.

The running psi for raw water for most generators is 4 psi. 3 psi will trip the sensor as well as 6 psi indicates a blockage in the heat exchanger.

IMG_3706.JPG
 
PlayDate said:
Agree about the sensors but for a different reason. The design of the sensors is to shut down the generator if one of them trips. Nine times out of ten the sensor is not the problem.....simply the messenger.

In this case, I would look from the intake port to the raw water pump. A Westerbeke is sensitive to having enough water flow. A blockage (or air leak) in the intake port, hose to strainer, strainer and the hose to the raw water pump can create enough restriction that it trips the exhaust heat sensor.

The running psi for raw water for most generators is 4 psi. 3 psi will trip the sensor as well as 6 psi indicates a blockage in the heat exchanger.

View attachment 111505
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But will it trip the sensor due to the restriction or only if the temp rises? I've had the temp gun on the manifold and exhaust elbow at time of shut down and they are not "hot" when this is happening. My exhaust water flow seems to be on par with the normal flow I get usually. It is also the normal luke warm temperature and does not seem to fluctuate at all while running.
 
mratlndmrk said:
Pardon my ignorance but I'm not 100% sure I know what that is what would I plug into that?
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don't need to plug anything into the outlet on the front. There is a male plug on the back (not shown) that you would plug into an extension cord, or straight into one of your 120v outlets. Now you can monitor voltage and frequency.
They are 15 bucks on amazon.
4143rMVuYbL._AC_SL1000_.jpg
 
mratlndmrk said:
But will it trip the sensor due to the restriction or only if the temp rises? I've had the temp gun on the manifold and exhaust elbow at time of shut down and they are not "hot" when this is happening. My exhaust water flow seems to be on par with the normal flow I get usually. It is also the normal luke warm temperature and does not seem to fluctuate at all while running.
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What you describe for symptoms seems temp related. After working on a lot of these generators over time.......the smallest thing can cause a raw water temp issue. The wrong impeller. A bad O ring on the pump cover. Debris in the line or heat exchanger.....the list goes on.

The other safeties are for oil pressure and engine temp. When diagnosing a problem generator......I slap gauges on the generator to see what is going on. Oil pressure and engine operating temp are easy to monitor with a set of analog gauges and rule out those two safeties. Once you rule those out....the only one left is exhaust temp which is why I built a pressure gauge to monitor the raw water psi.

Yes a wonky fuel pump can mimic a temp problem but again....putting a fuel pressure gauge on rules that out pretty quickly.

I think I have seen just about everything that can go wrong with these things and by far raw water flow is the single biggest issue for Westerbekes.

If the gauges all read okay then it is on to the wiring and electronics. A broken wire or bad connector can also mimic a temp related problem but they usually restart immediately without holding the preheat switch down (bypassing the safeties) to keep it running.
 
PlayDate said:
Agree about the sensors but for a different reason. The design of the sensors is to shut down the generator if one of them trips. Nine times out of ten the sensor is not the problem.....simply the messenger.
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Totally agree on the sensor not going bad, was only mentioning it to point to the area to look into. Other wise it's an open void and your throwing dart's at a barn.
 
Just an update on my issue....I haven't done a thing and it's now running fine (knocking heavily on wood). I've run it three times in the past week successfully (longest stretch 4 hours). I'm sure it will rear it's ugly head again and I thank you all for the suggestions of things to look for should it start acting up again.
 
mratlndmrk said:
Just an update on my issue....I haven't done a thing and it's now running fine (knocking heavily on wood). I've run it three times in the past week successfully (longest stretch 4 hours). I'm sure it will rear it's ugly head again and I thank you all for the suggestions of things to look for should it start acting up again.
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Monitor your voltage and frequency. cheap and easy to do.
 
Follow up question/issue. We crank up the generator and load it with breakfast (coffee pot, water heater, device chargers and sometimes AC) After about an hour it shuts off. Westerbeke 4.5 BCBG 650 hrs. Cranks right up and runs fine afterwards (although haven't pushed for any great length of time).

Question - How do I go through the various sensors (and in what order) to find the problem? If I bypass the sensor and it runs, bad sensor or vice versa?

This weekend is oil changes (motor and governor), plugs and impeller. Maybe that's the trick.

All help appreciated.
 
Check water intake strainer. Its happened to me
 
So the engine sensors are 1. Oil pressure. 2. Coolant temp. 3. Exhaust temp. 4. Sometimes an oil level sensor. 5. CO2 sensor
All that I have encountered go to ground when they fault so simply disconnecting them will keep them from going to ground. Just be careful because if there is a problem and the sensor is disconnected severe engine damage is possible.
 
Posting here as a future note to self. Sometimes it’s not the sensor, but instead the connectors. They are mostly push on terminals. Found corrosion on the two plugged into the water temp switch on the side of the block. After 25 years, even under the rubber boot, moisture will get there. Classic shut down when the bypass switch was released. Fixed in 5 minutes.
 
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