Westerbeke 12.5k - won't run when releasing Pre-Heat switch

[HenryD]

Hello,
I am trying to help a buddy boat with their Westerbeke and I have run out of my limited knowledge. They have a 12.5k Westerbeke that will start and run as long as the pre-heat switch is held on.
The owner has replaced two pre-heat switches (remote and main panel)
The main control panel is not powering but the owner disconnected and the genset behaves the same using the remote panel.
My first guest was the oil and overheat switches - connected around them and the problem stays the same.
The main fuse is labeled 8amp but has a 25amp fuse...it has blown and replaced with a 20amp, would not run, put 25amp and it will start but not run.
The owner is guessing it is a pre-heat fuel solenoid but is not sure how to test.
Other suggestions or thoughts. He is aboard the boat, I am 5 hours away but working with him over the phone.

 

[High Wire]

Is this a BTD model?
Is this a long term problem or did it just happen?
Does the solenoid pull the FI pump lever all the way to the left?
The Pre-heat switch bypasses the low oil pressure, the High Exhaust temp, and High Coolant temp, and OPTIONAL (if installed) switches on start. Optional would be things like Fire or Low Cooling Water Flow switches.
Does it have the solenoid power mod installed?
The BTD has a emergency shutdown switch mounted on the electrical box on top of the generator. Make sure its in the RUN position.

I'll try to post those here but they are only good for BTD model.

 

[Crusty Chief]

I just replaced the exhaust temp switch on my 8KW westerbeke because of the same problem. Now runs fine.

 

[micheln]

Just had the same thing on my westerbeke beda 32, was a diode

 

[Madhatter53]

There’s quite a few shutdown switches most can be bypassed to see which is killing it. Some are normally open and some closed so depending what type will dictate your bypass attempts. Could also be the circuit board. Try googling the type of genset and issue.

 

[Lepke]

Probably a safety, but besides them, the stop solenoid is usually powered when the engine is running. If you have to run the generator, you can run a wire from 12V+ to the stop solenoid (usually in or near the injector pump). Then start the engine and remember you're running without safeties. To stop, disconnect the wire.

 

[motion30]

This is classic symptom of one of the warning sensors being bad. Test the sensors and you will find your problem

 

[High Wire]

Re-reading the OP, with the control power fuse blowing it is symptomatic of a sensor switch grounding. When you bypass the switch make sure it is completely disconnected from the circuit to eliminate the ground. Check all the wiring for chafed insulation rubbing on metal.

 

[Chrisjs]

My recollection is a bit fuzzy but I had a similar problem when I first got my (used) boat. The 12.5KW WB would not start. Fortunately my dock neighbor had the simple answer. The solenoid was sticky and had not released. All it took was a light tap with a wrench and some WD40. Ran like a top for the next 8 years!! So, check the simple things first!!