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Northern Lights 38kw loses RPMs then shuts down

Discussion in 'Generators' started by Danvilletim, Aug 29, 2021.

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  1. Danvilletim

    Danvilletim Senior Member

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    Wll run an hour or two and then shutdown when heavy load kicks in. ( chillers). You can here rpms drop and hertz goes down. Sometimes recovers and sometimes doesn’t.

    Filters are clean, new turbo, and only 1700 hour.

    Norhern Lights is suggesting adj value clearance, back pressure testing to start with. Any other ideas?
  2. Pascal

    Pascal Senior Member

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    These symptoms are almost always a fuel problem. Did it start suddenly? Pardon the simplistic question but has the secondary been replaced too?

    I d start with the fuel pump. Or assuming you have priming pumps, try running it to supplement the gen fuel pump.

    I don’t see how it could be a valve clearance especially on a low hour NL. If it was, the problem would happen as soon as a heavy load is out on it.

    another possible test would be to load it up right away. If it doesn’t shut down then, you know it s not a valve or engine issue but fuel where it takes a while for the fuel starvation to build up
  3. Capt J

    Capt J Senior Member

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    When you say the filters are clean. Are they NEW? I've seen engines with fuel pressure issues and the filters looked quite good, but were clogged.

    I'd start by calling a Northern Lights dealer. It could be the governor. It could be the fuel pump, a sensor etc. You could spend hours and hours and thousands of dollars throwing money at it and still not fix it.
  4. Danvilletim

    Danvilletim Senior Member

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    Lol. 6k so far with Perfoemance Power out of Savannah. An auth dealer! Going to try to get someone on board while up North. My appointment is in 2 1-2 weeks.
  5. Pascal

    Pascal Senior Member

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    Intermittent issues are tough to diagnose but $6k seems a bit high :) what did they do for that kind of money ???

    as much as I hate throwing parts at a problem, I would start with the fuel pump. Pretty cheap and it s always good to have a spare anyway.

    I don’t think a sensor would cause the engine to stumble... I just don’t see that scenario. A sensor will stop the gen clean.

    did the problem start suddenly? Out of the blue or after some maintenance.

    I would replace the racor and the secondary again. Just to be safe.

    next would be the governor.

    after it stops, does it restart right away? Do you have to reprime or crank for longer than usual ?
  6. Danvilletim

    Danvilletim Senior Member

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    Managed to run all night on this genie. Then I intentionally loaded the boat and it failed. I think fuel pump sounds like a good start. Next the governor.
  7. Capt J

    Capt J Senior Member

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    How about putting gauges on it and properly diagnose it. Sounds more like a heat exchanger and as you load it, it hits the overheat shut down. Easy enough to put a fuel pressure gauge, temp gauge, and etc.
    ArielM likes this.
  8. Pascal

    Pascal Senior Member

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    A cooling issue doesn’t cause a stumbling and slow shutdown as soon as load is applied. I may be wrong but that’s how he described the symptoms. A safety kicking in result in a quick clean shuts down
  9. DOCKMASTER

    DOCKMASTER Senior Member

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    So if the fuel pump and governor have not been looked at, what the heck did Performance Power do for $6k? Perhaps these guys are better at working the gen end and not so much the engine side? Based on your description of symptoms, I would think that after basic filter checks the governor then fuel pump would be the first things to look at.
  10. Capt J

    Capt J Senior Member

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    I've had it where the heat exchanger was borderline.......light loads coolant temp would run near the safety shutdown, when more load was applied the engine created more heat, hit the coolant temp safety shut down and shut down.
  11. Pascal

    Pascal Senior Member

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    That could happen but every time I ve had cooling issue there was steam in the exhaust before. And again, it s a clean shut down not the stumbling and almost recovery he described
  12. Marblehead01945

    Marblehead01945 Member

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    Interesting- I had a similar issue with a Kubota Stamford Generator this past weekend. It was very hot out and the generator was cutting out after about 30 minutes. Water pumping, no signs of over heating or other issues. Troubleshot it and it turns out one of the AC units evaporators was frozen solid and it just loaded everything down. Shut that AC unit off and everything is running fine. I would look around for any and all external things as well.