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cemter's avatar
cemter
Explorer
Aug 13, 2016

Onan Emerald Frequency Drops with no load -- HELP

Hello. I have an Onan Emerald Model 5BGEFA11579P in a 2001 Georgie Boy Pursuit. It starts and runs as long as I hold the start button. When I release of the start button, sometimes it stays running, and sometimes it kills. When it stays running, it does so for anywhere from 10 seconds to 5 minutes. When it kills, it kills like you hit the kill switch (no sputtering or anything like that). I have confirmed oil level and ohmed the oil pressure sensor and confirmed proper operation. I have also verified proper voltage output. The frequency output seems to be causing the problem. Using a frequency meter, I have confirmed that when it continues to run after the start switch is released, it has and frequency output of 65Hz (no load). It runs for 10 seconds to 5 minutes continuing to output 65Hz, and then will suddenly drop to 16Hz and then it kills. Thoughts? Any help would be appreciated!
  • cemter's avatar
    cemter
    Explorer
    Aug 13, 2016
    I did some additional testing. Engine kills when the voltage goes away from the generator leads into the control panel box. What are reasons that a generator stops making power?
  • ksg5000's avatar
    ksg5000
    Explorer
    Aug 13, 2016
    Onan frequency is directly correlated to engine speed (rpm's) - suggest you focus on why the engine is turning itself off.

    Two common reasons for generators to quit after you release start switch are defective oil pressure sensor or failure to produce electricity. I believe you can jump the oil pressure sensor to eliminate that as a cause. One of the common reasons that generators run for a while and suddenly quit are fuel related - weak/defective fuel pump, fuel filter, or even tiny hole in fuel line.
  • j-d's avatar
    j-d
    Explorer II
    Aug 13, 2016
    Admittedly an odd name to help with generator service, but take a look at Flight Systems. They have more info on some models than others, and if I recall they had some troubleshooting on Emerald Series.

    When you start it, a lot of the genny's monitoring systems are disabled. When you release into RUN, one or more probably sees something it doesn't like.

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