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Northern Lights Genny -hard to stop

Discussion in 'Generators' started by yachtbrokerguy, Sep 29, 2008.

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  1. yachtbrokerguy, Sep 29, 2008
    #1
    yachtbrokerguy

    yachtbrokerguy Guest

    I was on board a clients yacht today. When shutting down the 32 kw Northern Lights, the engine wanted to run on without stopping, but at a slower RPM. Since I had the sound enclosure open, I simply grabbed the fuel shut down lever and stopped the engine.
    My guess is the stop solenoid is getting tired and does not throw the fuel shut off far enough to totally cut all the fuel. Would the engine guys here agree with that? Just get a new solenoid, or might it be something else? The generator has had very little use lately.

    Tucker Fallon
  2. K1W1, Sep 30, 2008
    #2
    K1W1

    K1W1 Senior Member

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    Hi,

    It sounds like something simple going on here.

    Maybe the stop solenoid is not traveling fully owing to rust or some other crud restricting it's movement.

    Without knowing anything about Northern Lights Gensets it's hard to suggest much else.
  3. yachtbrokerguy, Sep 30, 2008
    #3
    yachtbrokerguy

    yachtbrokerguy Guest

    No rust or crud, actually the solenoid has no white paint on it making me think it is not original. If someone installed a 24 volt solenoid on a 12 volt system, would this be a result?
  4. Fishtigua, Sep 30, 2008
    #4
    Fishtigua

    Fishtigua Senior Member

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    We had the very same problem a few months ago, so we bought a new solenoid; ace, job done. But they charged over $350 for a new one!!!!!! :eek:

    Fish
  5. wdrzal, Oct 1, 2008
    #5
    wdrzal

    wdrzal Senior Member

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    Most solenoids you can swap the coil to the correct voltage & amperage. find a cross reference chart for that brand solenoid. Take into consideration the pressure differential .

    You also have to check the MOPD (maximum operating pressure differential) Say the MOPD is rated @ 50 psi . That means there can't be more than 50 psi between inlet & outlet. Or they wont close or open properly. If you require a 100 psi MOPD and have one rated for 50 psi,it just won't work. You would need a 100 psi MOPD.

    Only other thing many solenoids have orifice sizes,1/8",3/16" 3/8" and so on, these can be much smaller than the inlet and out size.Be sure to check that also. They are flow restriction/application specific.

    Most are manufactured from brass but stainless are available.
  6. C4ENG, Oct 24, 2008
    #6
    C4ENG

    C4ENG Senior Member

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    I have had the fuel shut off solenoid switch malfunction before on a 3304 CAT gen. I held down the stop botton and nothing happened.
    On the Cat engine I had to remove the soleniod with wrenches before I could get to the fuel lever to shut it off.
    I never looked into why the solenoid had failed. I just replaced it.
    But on the northern lights gen sets I believe you have an electrical actuating arm that controls the rpm and the shut off as well. There can be a lot to speculate as to what could have malfunctioned. I would probably first start by manualy checking that the arm is going back to zero postion with the gen off, moving it to a run position. If it is, then I would second check that some sort of outside voltage is not keeping it from going back to zero by keeping a volt meter on the soleniod terminals and watch what happens when the stop button is pushed.
  7. Clectric, Oct 26, 2008
    #7
    Clectric

    Clectric New Member

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    It could also be worn/faulty seals allowing leakage. This happened to me last summer. The shutdown sol. worked but the worn plunger seals allowed fuel to continue to flow at a reduced rate. New seals and voila,shutdown.
  8. VikHatBer, Oct 26, 2008
    #8
    VikHatBer

    VikHatBer New Member

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    On my 20 kW Onan generator, you have to hold the switch down for 5 seconds before the generator shuts off.

    This is "the beauty of the beast"