Westerbeke 8.0 BCDT generator starts, then stops.

[jibstay]

My Westerbeke 8.0 BCDT generator starts perfectly, but then shuts down after a few seconds.

I’ve tried jumpering both the temperature sensor and the oil pressure sensor.

I can’t find an exhaust temp sensor.

I’ve replaced the current timer module.

The fuel system is perfect, new Racor.

The heat exchanger is clean.

It puts out tons of water in the exhaust.

Even with the sensors bypassed, the red light on the panel comes on as it shuts down.

Any advice would be appreciated. Thanks.

[jibstay]

I should also mention, I disassembled the control panel, 046149, which isn’t made anymore, and inspected the circuit board. I didn’t find anything that looked blown.

[jibstay]

The red light on the panel indicates oil pressure or temperature sensor.

[Bill O]

Do not have the same Westerbeke generator that you have, but know they do have good technical documents online. Here is the link to the trouble shooting manual for your gen.

Hope it helps.

[jibstay]

Thanks

[Bycrick]

If your Westerbeke has the same wiring as my 4 kw, the important thing to remember about the stop circuit is that it begins at the STOP switch, passes through all the harness wiring, wanders all around the motor (over temp and oil pressure and maybe exhaust temp switches), fuel pump and eventually ends up at the run solenoid. A loose or bad connection anywhere will stop things dead. Don’t forget to check the ground wire or connection on the run solenoid. It’s far more likely to be a bad wire or bad connection than a failed switch.

The solenoids draw a lot of current when they pull in. There’s a mechanical switch inside the solenoid that reduces the current after the solenoid has pulled in completely. If the solenoid isn’t positioned properly, it won’t switch. A loose connection there will also stop things.

It took me 2+ years to find my bad spot. Good luck.

[jibstay]

Good advice, thanks.

I had a mechanic replace the fuel solenoid with a used one that he had. The generator started, ran, and produced electricity. However, the red light still came on. When I pushed the stop button, all the lights on the control panel went off, but the generator kept running. The mechanic had to block the air intake to shut it down. He put the original solenoid back in and we’re back to shutting down almost immediately.

[sainted]

As was noted above, the voltage to pull the fuel solenoid to the run position does wander from the engine to the remote panel and back, and a bad connection in that circuit could well be the cause of the problem. I diagnosed and fixed one on a customer's boat a while back.

But before you start tracking the bad connection down, find the exhaust temp sender. There certainly is one and they do fail, so make sure its not the problem.

If that sender is ok, you're going to have to take the schematic and trace the circuit, measuring voltage with the circuit energized at many points along its path. Yes, it has to be energized because you're looking for voltage drop, and that only occurs when current is flowing. Start at the circuit breaker in the control box on the generator and work your way to the panel and then back to the solenoid. Yes, it's tedious and time consuming. You might want to hire a good marine electrician to do it for you. But that's the only way this problem gets fixed. Use one good ground on the generator as your reference. Having an insulation piercing probe will make the job easier.

For the generator I fixed, the problem was in a too small wire in the remote panel. I had to move some stuff around to get a more direct connection between the B+ wire from the generator to the run/stop switch, which essentially by-passed the too small wire.

Good luck!

Scott

[jibstay]

Thanks Scott. I’ve closely examined the wiring diagram for the 8.0 BCDT and there’s no exhaust temp sensor. I’ll check again, though.

[Bycrick]

The exhaust temp sender was optional, depending on the model. The 4kw that I have never had one. The 8kw one did. Strangely the 15kw one didn’t.

From memory, there was a service bulletin years ago that modified the wiring so that the fuel pump and solenoid power were supplied from the glow plug relay when you were starting the motor. Once you released the PREHEAT switch, the power was supplied by the long path through the panel and harness. Hence the common symptom that it starts OK and stops the minute you release the PREHEAT switch. Check that the field modification is actually installed.

Most of the sensor connections are 1/4” spade connectors. Over the years, the female side looses its springiness, which results in poor/loose connections. Don’t be tempted to try to squeeze them together to make them "tight" again. They’re a pain to replace because the wires don’t have any slack. Don’t ask me how I learned that.

[jibstay]

Mine is a little different. I hold the Stop and Start buttons together to preheat. Then release both buttons and press the Start button to start it.

If I understand things correctly, the current timer module bypasses the sensors long enough to allow oil pressure to come up. I could be mistaken. I’m tempted to disconnect all of the wires in the fuel control circuit and replace them one by one with new wires.

[caseycody]

try to bleed and get air out of lines. kohler has a screw you can remove to bleed it. don't start while bleeding it, watch for antifreeze to come out of drain hole replace cap and check over flow bottle. keep filling to you see it come out of hole

[Scrimshaw4]

Have had similar problems. Turned out to be an air leak in the fuel line / filter seal. A way to isolate is to use a fuel can and hose and then start at the fuel pump and work your way back to see where / when the stop occurs. JMHO

[OldGreyB]

You state :" even with the sensors bypassed the red light on the panel comes on as it shuts down"
I am not sure what you actual mean by "bypassed". It is hard to help without understanding what you have actually done here. So back to basics will help the Forum brain trust help you.

If your Westerbeke 8.0BCDT wiring is as per attached 41990Rev A schematic, the first way the Red light can come on after cranking (Yellow Light) and heading to run condition(Run relay engergised ,Green Light if good) is either the Water Temperature or Oil Pressure Sensor switches are closed and the two safety relays are staying energised as the run cycle begins(Red Light), resulting in the shutdown.

The Oil pressure is Normally Closed going Open on good oil pressure.
The Water temperature is Normally Open going Closed on High Water temperature

As these sensors are the first in line in the control system, we should ensure this basic circuit is working as designed before moving on with further fault finding. To test each sensor:

1) On a cold engine disconnect the red/ yellow signal wiring from the Water Temperature sensor tab. With a multimeter on Ohms , one lead is attached to the black wire on the Water Temperature sensor and one on the tab from the disconnected red/ yellow signal wiring . This should provide a reading O ohms continuity ( Open) If it reads any Ohm value when cold then it is remaining closed and is faulty and should be replaced. Once this check is completed and results confirmed good, or faulty sensor replaced, reconnect the red/ yellow signal wiring.

2) Disconnect the red/ yellow signal wiring from the Oil Pressure sensor tab. With a multimeter on Ohms , one lead attached to a good engine ground one on the tab from the disconnected red/ yellow signal wiring, this should read 100% continuity to ground. (Closed).
You now can remove the Oil Pressure sensor and apply appropriate pressure via a test pressure pump, (40 - 60 psig) and see if it goes to 0 Ohms (Open) between the tab and the sensor body. If it does not, then if is faulty. If it does, then one should check your engine oil pressure with a mechanical gauge.

Alternatively, if you are confident you have good engine oil pressure, then with the multimeter leads still on the oil pressure sensor tab and ground, crank the engine. If this does not go to 0 Ohms, then it is faulty and should be replaced or you have blocked oil feed gallery. CAUTION: As any diesel engine, do not crank extensively with the cooling water feed valve still open. Additionally, as I read the Westerbeke 8.0BCDT 419900Rev A schematic, it appears to be not fail safe, so if both the Oil pressure sensor is disconnected from the control circuit, there is the potential the engine will run with no oil sensor protection, ( the red light will stay off) so if you do this test this way, it may run, so be prepared to push the stop button.

Once the above tests have been confirmed and results posted, we can help trouble shoot the circuit further. Also please confirm your run solenoid has three wires ( run, hold, ground )as per 419900Rev A schematic, or does it have an internal switch as per post #6?

Suggest you try the above and report back to the forum.

[Boatyarddog]

Originally Posted by Bill O

Do not have the same Westerbeke generator that you have, but know they do have good technical documents online. Here is the link to the trouble shooting manual for your gen.

Hope it helps.

This is NOT the diesel genset.
Here's the troubleshoot guide for the bctd 8.0 check it out.
https://www.westerbeke.com/operator'...erator_man.pdf
Boatyarddog