Need help adjusting frequency on Koehler 5E

Discussion in 'Electrical Stuff' started by boatrboy, Sep 27, 2022.

  1. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    2006 340 Sundancer

    When I purchased the boat this May, the previous owner had to replace the carb. When we surveyed the generator ran great and the voltage was checked but the surveyor did not have his frequency meter and suggested I verify the speed was correct.

    Fast forward - I really did not use the generator this summer other than run it with a load at the dock on occasion. I recently ran it with the air conditioning on to put a bigger load on it and noticed a sound which I can only describe as a slight squeal from the a/c unit. I wondered if the frequency was in fact off since there is no noise on shore power.

    I borrowed a meter with HZ reading on it last night and saw it was at 58hz. I left the manual at home so I just raised the idle screw to see if it would raise. It did but fluctuates more that I expected.

    What is correct method of checking and adjusting the frequency? The manual has me scratching my head. Should I have set it with no load? I noticed when I turned on the stock inverter the hz dropped to 56. Is there more than just the idle setting?

    Thanks in advance,

    Mark
     
  2. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    The frequency output is a direct function of engine speed. Depending on if you have a 3600 RPM or 1800 RPM unit, that should get you 60hz.

    It is typical for the hz to sag slightly, and 58 vs 60 at full load wouldn’t very noticeable except to some electronics…

    Don’t know you model, but the manual would have the setting proceedure and the spec.
     
  3. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    The model is 5E. 3600 rpm.

    Being more specific - the manual I have has very little for pictures and talks about setting pots to get 60 hz. I too assumed rpm will set frequency but am not sure if I’m supposed to adjust something other than the idle screw. With or without load? Etc.

    How did you adjust yours and how did you verify it?

    Thanks
     
  4. SKybolt

    SKybolt Well-Known Member SILVER Sponsor

    Nov 11, 2014
    Kent Narrows, MD
    460 EC
    Detroit 6v92TA
    (Low profile's)
    Alison Gears
    Westerbeke
    12.5kw Genset
    Yes you need to set the RPM and Frequency with the pots. The RPM one is for rough adjusting and the Frequency is for the fine adjust. Not quite sure on that model but, I don't think it matters about being loaded or not. But if it doesn't state it, I would use a 50% load once the Frequency is within +/-2 hz of 60. Then put on a 50% load and re-adjust.

    You need a Digital Volt Meter capable of frequency to read the frequency.

    Like @dtfeld , mine is also set manually. I set the RPM by the frequency at 50% load.
     
  5. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    Thanks Sky - where are these pots? My manual doesn’t really show them other than in schematic form. As mentioned above I do have the meter which is how I found out the frequency seemed low.
    1D1C29B0-E9A1-4B01-B652-88495848D9D5.jpeg
     
  6. SKybolt

    SKybolt Well-Known Member SILVER Sponsor

    Nov 11, 2014
    Kent Narrows, MD
    460 EC
    Detroit 6v92TA
    (Low profile's)
    Alison Gears
    Westerbeke
    12.5kw Genset
  7. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    Thanks - that’s the same manual I have - I will try to follow this procedure later this week.
    It’s weird that everything seems to work fine but that whine when running the ac must be due to the low frequency. My electrical engineers at work tell me if it was higher hz it would be less problematic. Hoping this weekend to fine tune it. I am still not sure why after the po did a carb change why I need to readjust frequency pots…. One of my engineers says it should only fluctuate +/- 1 hz.
     
  8. SKybolt

    SKybolt Well-Known Member SILVER Sponsor

    Nov 11, 2014
    Kent Narrows, MD
    460 EC
    Detroit 6v92TA
    (Low profile's)
    Alison Gears
    Westerbeke
    12.5kw Genset
    Thats in a perfect world. An under powered 5K marine generator is never going to be able to do that when it see's a 50% load switching on/off frequently. The reason it runs at 3600 rpm is to help the engine keep up with torque demands of the generator load.
     
  9. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    To close this out (at least for now:)), I realized that the idle screw I was adjusting was just that, an idle screw. I noticed that the governor has a screw adjustment so I cranked that in a little and saw the frequency increase to where I was more comfortable. It’s not holding as steady as the shore power as sky noted, but it stayed up at the 61/59 HZ. I hoped for. I then checked the rpm and saw it was right on 3600 with this setting.
    The final test and reason for my checking all this, was turning the a/c on and listening for the whining I noticed earlier. For whatever reason the noise is gone. I would like to believe the low frequency was the cause.

    So after a few hours of run time I changed the oil, plus oil and gas filters, impeller, plugs and winterized it! Should be good for next year.
     
    SKybolt, dtfeld, Phil S and 1 other person like this.
  10. KevinC

    KevinC Well-Known Member

    Feb 25, 2011
    Long Island, NY
    2004 340 Sundancer
    Twin 8.1 V-drives
    I would also suggest draining the carb too to get out any remaining gas. After having to change out my fuel system this year it was suggested to me that it is simple protection.

    -Kevin

    -Kevin
     
  11. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    Not a bad idea - is there an easy access drain screw?
     
  12. KevinC

    KevinC Well-Known Member

    Feb 25, 2011
    Long Island, NY
    2004 340 Sundancer
    Twin 8.1 V-drives
    IIRC there is a screw with spring on the bottom side if the bowl.

    -Kevin
     
    Nater Potater likes this.
  13. Wanderer 290

    Wanderer 290 Well-Known Member

    756
    Jul 1, 2019
    Traverse City
    01 sea ray 290 sundancer
    Twin 5.7 b3’s
    An easy way to drain the fuel from the carb is to start it and then disconnect the fuel pump and let it run until it dies.
     
  14. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    True -but at this point it already has antifreeze in it and the plugs have been sprayed with fogging oil. Ill try to drain it when I'm in there next.
     

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