ONAN Generator Performance

Discussion in 'General RVing' started by JimE, Jul 27, 2004.

  1. JimE

    JimE Senior Member

    I recently purchased my first motorhome, a 1993 Winnebago Brave 31', and drove cross country. My generator is an ONAN 6.5, and it has a tendency to throttle up and down, causing the lights to go bright and dim constantly. Someone told me this was common and there wasn't much I could do about, but I can't believe that. Has anyone had the same experience and have any advice on how to fix it?
     
  2. Will Daniels

    Will Daniels New Member

    ONAN Generator Performance

    Jim: I dont believe it either. The unit should run steady unless you increase the load. Sounds like a fuel problem to me,have you done the obvious and changed the filters?
     
  3. Gary B

    Gary B Senior Member

    ONAN Generator Performance

    Hi Jime, welcome to the forum, Will is right on they need to run steady, even under load the change should be very suttle, varing changes in RPM change the voltage and the cycles, as Will posted check the fuel system, filter, you can check for correct rpm, voltage & cycles by getting a inexpensive AC voltmeter that plugs into an outlet, and a 100 VAC clock with a sweep second hand(like the older alarm clocks) and a stop watch. Start the generator check the voltage on the voltmeter, then plugin the clock and time the second hand aginst the stop watch, if the clock beats the stop watch to 1 min. then the rpm are too high and if the stop watch is in first place then the rpms are to low, you set the rpms by adjusting the stop screw on the carb., good luck. :) :laugh: :cool: :bleh: :approve:
     
  4. Icky

    Icky New Member

    ONAN Generator Performance

    There is a possibility that the air cleaner is dirty or the carb. is set too lean. Either condition is one cause of governor hunting. Check the generator exhaust to see if it is producing a black smoke, this would indicate too rich a mixture. Adjust the carb. mixture, or maybe the air filter is dirty and causing a rich mixture. If the carb. is adjustable, turn the mixture screw counterclockwise to make it real rich. This will cause even more black exhaust smoke and more hunting. Then slowly turn it in clockwise until the engine runs steady. If the engine sounds strong, but has an regular stumbling, you might want to replace the spark plug. Other than that, you will have to take it to a small engine shop. It should run very steady either at full load or unloaded. Hope this helps.
     
  5. JimE

    JimE Senior Member

    ONAN Generator Performance

    Thanks for the advice, I'll give it the once over this weekend and let you know how it goes.
     
  6. janicenlarry

    janicenlarry New Member

    ONAN Generator Performance

    Jim you need to have this unit looked at. If I have learned anything after years on the road, when you have an Onan genny problem, go to the Cummings-Onan service center. They treat you great (have plug-ins if reqd) and get the job done right and economically. DO NOT let an RV dealer dick around with it. You will have nothing but grief. Once you get this unit running right, be religious in maintaining it and running it at least once a month for an hour under load. Underused gennys are trouble.
     
  7. JimE

    JimE Senior Member

    ONAN Generator Performance

    janlarmil, when I picked up the tune up parts at the Cummins/Onan dealer yesterday I noticed their prices were very reasonble for service, thanks for the advice. If a tune up doesn't do the trick, I'll be taking it to them.
     
  8. janicenlarry

    janicenlarry New Member

    ONAN Generator Performance

    Jim, on my last trip, while starting my genny remotely, I broke the starter. On my rig to get to the starter, the whole unit has to be removed & it is not on a slide out tray. They did the job in less than an hour with a min. labor charge of $80 with $200 for the starter. A dealer would have taken much longer at a higher cost. I do my own oil, air & oil filer changes and carbon blowout. The rest I leave to them
     
  9. fireman2237

    fireman2237 New Member

    ONAN Generator Performance

    We had onan generator problems and went to the closest onan service center. I can't say enough about these guys. They were Johnny on the spot with our appointment. Had us fixed and out of there within a hour and half. Service fee is 81.00 a hour but sure beats sitting there for a day trying to figure it out when you don't have a clue anyways.
     
  10. JimE

    JimE Senior Member

    ONAN Generator Performance

    Thanks for the advice. I replaced the air filter and cleaned the carb per the ONAN directions, and then replaced the fuel filter. The fuel filter did the trick runs smooth as silk now.
     
  11. rvlikens

    rvlikens New Member

    ONAN Generator Performance

    Something else to note. When I got my first RV (85 Fleetwood Jamboree, 25foot), the genset had 2hours on it. Yep, it looked new. It was fine till one day when I REALLY needed it (power outage in the MI/OH/NY area) it ran up and down and was putting out some black smoke. Smelled too rich. :dead: So, lucky for me, took it to a ONAN service center (who still had power.. ummm, wonder why) They first thought my carb was hosed up $$$. Then the tech sit down next to the unit. Scratched his chin and played with the altitude adjustment. The button was broke and it was set as though I was ontop of Mt Everest. He set it to the right altitude and sprayed some cleaner into the intake. It runs like a charm. Cost me about 100.00 for the 2 hours they spend working on it but cheaper then a new carb.
     
  12. rvlikens

    rvlikens New Member

    ONAN Generator Performance

    I just changed my oil. 2 years old and 66 hrs total on unit. Was a little black but I think that was from the time it was running way to rich. I also took out the plug and cleaned it. Now it's all shiny. Now the genset starts right up, about 2-3 seconds of starter and runs great.
     
  13. Poppa

    Poppa Member

    ONAN Generator Performance

    Another rule of thumb for the generator is to start it let it warm up then use a volt meter to check the voltage in the receptcales with no load on the unit, it should be about 130 volts.
    As to the cycling or hunting this is not normal and as al the others sounds like maybe fuel filter of carb adjustment.
     

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