Genset starts, but then stops

jeremyshaw

jeremyshaw

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My Kohler genset starts instantly, then stops a second later.

Two days ago and yesterday it would do this about 6 times, then run faultlessly.

Today it won't run after 50 attempts. (The Lifeline AGM is doing rather well!).

Every time it fires, then dies away after a second.

I have checked:

1. Fuel flow. This seems to be fine. We have a tank above the genset and when I undo the top bleed screw diesel flows out without any bubbles. Also the fact that it was running without any probs once it got going makes me think it is not a fuel problem.

2. Low oil pressure switch. I have jumpered the switch, no improvement.

3. High water temperature switch. Disconnected the switch. No improvement.

4. High exhaust temperature switch. Proved to have been already jumpered.

5. The manual says another possible cause is "no AC output". The genset is not running long enough to activate the amp meter I have, but putting a multimeter onto the breaker in the control box is giving me 30-60 volts, so I think it is starting to get going and this is not causing a shutdown fault.

That leaves me with the solenoid, which I think must be shutting off the fuel, but I can't test that.

Before I order a solenoid (probably worth having anyway) has anyone got any other suggestions?

Many thanks
 
Could be the plunger in that solenoid operating valve. Sometimes you get a flap of rubber peeling off and stopping the flow as soon as it starts.
 
Perhaps you can test the solenoid valve by removing it and the putting 12V across it to see if it opens fully. But first, is there anyway of removing the outlet from the valve to see if fuel is pumped as you try to start? Is fuel arriving at the inlet to the valve? Is there fuel at the injectors if you loosen off one of the unions?

Are there any relays to control the fuel soleoid valve or other components? I've an FP genset and the relays have been the root of a couple of similar problems.
 
Thanks for the replies.

I put direct 12v on the make-open terminal on the solenoid and the genset ran, but on the hold-open it didn't seem to stay open. I was testing some more and the solenoid fried because the make-open must have been on too long. So I think it must be the solenoid and I need a new one for sure!
 
The whole idea of the solenoid is that it is powered and will stay open .. Once the solenoid has gone to its maximum it should just stay there with the current applied .. Sounds like it was not seating properly and hence carried on trying to seat itself and fried in the process .. Make sure that if it is adjustable that it sits fully home .. We use them to open cash drawers and if they get muck in them they just keep trying to pull in .. They then get hot .. The plastic centre then deforms .. and they never work again .. Possibly just muck caused the problem in the first place ..
 
Thanks for that. As I understand it on the Yanmar engine fitted to the Kohler there is one terminal applied to get it open while you crank with a strong current and another to keep it open. I think it was the latter which failed. But I can't tell now because while testing it I probably kept the current on the first terminal on too long so it fried, as I was warned it might. So we need a new solenoid come what may I fear.
 
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