Fried electrics and battery

[MarkJohnson12345]

Terrific day out, sun and some sailing until the wind died.

Motor started several times during the day.

Moored up my pontoon this evening, the next door neighbour very kindly gave me a beer, and we nattered for 10 minutes or so.

Suddenly my boat engine just started up, all by itself!!! (Bukh)

A mad dash to the cabin, (not spilling the beer I have to say), the engine compartment was full of electriccy type smoke.

I tried to turn the engine off with the key, by turning it anticlockwise. Nothing happened.

So we now have to stop the diesel engine.

In the meantime the battery monitor is having fits, with all sorts of warning sounds coming from it, and I could see the voltage of the main battery dropping, 6 volts was the last time I saw it.

I switched off the main diesel flow thingy, but nothing happened other than the motor continuing to run. I took off the diesel tube from the tank to the primsary filter, eventually took off the main filter. The engine still took 2 to three minutes to run out of fuel.

My neighbor then said I could have stopped the engine by opening the decompressors. Thats something I have learnt tonight.

The wire from the fuel pump solenoid is fried.

There seems to several wires in the loom that are also fried.

Having stopped the engine, I switched off the batteries. I did not want to do that whilst the engine was running as I thought that would damage the alternator.

To see if there was any life anywhere I did switch on the mains battery charger. I switched on one battery, and the engine tried to start again.

So to make it all safe, I have disconected both batteries, and disconnected the mains.

The main battery voltage is les than a volt, the engine battery which was isolated is fully charged at 12.9 odd volts.

WTF went on??

I guess I was lucky that it happenend at the end of the day, and not when I was 10 miles away at anchor off the Gower coast.

I intend to get the local marine engineers to sort it, but would dearly love to know what went wrong.

Despite the potential cost, I can see a funny side to it, watch out if your flippin diesel decides to start it self, and sort out a strategy for stopping a diesel when the solenoid F****s up.

 

[William_H]

It does sound like an electrical foul up in the engine control circuits. I am not familiar with Bukh so can't give any technical theories. It is especially surprising the solenoid feed wire has burnt. I would suggest that by the time all the wires are rpelaced and the control panel is fixed you won't have any problems.
However you should try to get your discharged battery recharged soon before it is damaged. good luck olewill

 

[oldsaltoz]

Could be the starter motor solenoid shorted or the supply to it shorted, it would have some fuel in it so could start.

Let's hope it was the supply to it rather the starter, very expensive little item to replace.

 

[Malish]

For your future ref (!) a quick way of stopping a diesel is to starve it of air (rather than fuel as you did) ease of application depends on the style of air filter but placing a large oily rag over the air intake usually does the job.

 

[Shekel]

On my engine it has a stop solenoid. I can stop the engine by manually moving the lever that the solenoid acts on. Mind you I'm not sure I would like to dive in there and breathe too many of the fumes.

 

[Shekel]

Just realised it wouldn't have helped in this situation as your fault would just have allowed the engine to restart. Sorry. Must think about posts more.

 

[morgandlm]

Wow - bad luck. I would assume that there is a short either behind the control panel (starter switch) or in the engine loom. I would guess the former. The fact that it tried to start again probably means the starter is still ok which is good news. I have a bukh DV10 and my instinct would have been to use the exhaust valve decompression lever and turn off the master switch and accept the risk of blowing the alternator diodes. (Cheaper than a written off starter motor). Please post your eventual findings so we can learn!
Morgan

 

[MarkJohnson12345]

Had a closer look today in the daylight.

The back of the alternator and its wires seems to be sound. No burning anyway.

As you note I supect the starter motor is OK.

The wire to the stop solenoid is a crisp! as are a couple of wires in the loom.

I suspect something went ti*s up in the control panel.

Anyway, man has been booked to fix it, so will keep you posted.

 

[jeremyshaw]

That's truly weird and understandably scary.

Back to basics: the engine could not have started at a pontoon without the starter motor activating. That suggests a short somewhere in the harnesss/control panel. You say that several wires are fried, so there could have been consequential faults with one frying wire burning the insulation on others. I think it will need careful tracing to ensure that all the damage is identified and fixed. Bummer...On the bright side, no fire!