Forum Discussion

two_travelers's avatar
two_travelers
Explorer
Nov 24, 2017

Generator start issue

Went to turn on generator, Onan 4KW, today to run it for a while. Primed it several times then hit start. The first crank of starter motor sounded like a dead/low battery then it sounded normal. Same thing happened several times since it did not start on first try. What battery is the generator hooked to? Both house and chassis showing good charge voltage (14+V). With no AC battery voltage was about 13V. After running generator for an hour I turned it off waited a few minutes then hit start again. No problem this time. Any ideas??
Class A
  • gutfelt's avatar
    gutfelt
    Explorer
    Nov 24, 2017
    two travelers wrote:
    Went to turn on generator, Onan 4KW, today to run it for a while. Primed it several times then hit start. The first crank of starter motor sounded like a dead/low battery then it sounded normal. Same thing happened several times since it did not start on first try. What battery is the generator hooked to? Both house and chassis showing good charge voltage (14+V). With no AC battery voltage was about 13V. After running generator for an hour I turned it off waited a few minutes then hit start again. No problem this time. Any ideas??


    maybe got a battery going bad seen where voltage with no load reads ok but under load(trying to start gen set) it(battery volts)drops dramatically
  • Matt_Colie's avatar
    Matt_Colie
    Explorer II
    Nov 24, 2017
    Two,

    We have seen this a lot over the years.
    It will turn out to be either a bad battery that recovered after being charged.
    Or, it is a bad connection in the starter power circuit. This one is easy a cheap to fix if you do the complete diagnostic.

    Matt
  • SidecarFlip's avatar
    SidecarFlip
    Explorer III
    Nov 24, 2017
    Sounds to me like a high resistance (corroded) connection on the genny starter motor.
  • Tinstar's avatar
    Tinstar
    Explorer
    Nov 25, 2017
    Just FYI, in case you don't know; You can use your battery boost switch on the dash to give it the extra power needed from a cold start.

    It could be wired either way. Some wire the genset to the chassis battery others, like mine, use the house batteries.
  • path1's avatar
    path1
    Explorer
    Nov 25, 2017
    I have one spade connection on the solenoid that I have to wiggle every so often. I'd replace by now but it is riveted to solenoid. All not bad though. When I have to take off the cover to start, good time to make sure no gas leaks. I've tried die-elec grease, bending it a little, metal paper clip stuck in connection etc. Sometimes I get a big burb out of starter, sometimes nothing, sometimes clicking noise.
  • ksg5000's avatar
    ksg5000
    Explorer
    Nov 25, 2017
    Clean your battery terminals as well as the battery grounds - also clean the battery contact/grounds on the generator. Lastly - if you start the RV engine it will place both chassis and coach batteries on-line which will help start the generator.
  • jerseyjim's avatar
    jerseyjim
    Explorer
    Nov 25, 2017
    Just to add....on the same general topic, my generator, if the temp is say, 40F or below simply refuses to start. Spins like a top, but won't fire up.

    When warm, (termperaturewise) starts and runs. Any ideas?
  • gutfelt's avatar
    gutfelt
    Explorer
    Nov 25, 2017
    jerseyjim wrote:
    Just to add....on the same general topic, my generator, if the temp is say, 40F or below simply refuses to start. Spins like a top, but won't fire up.

    When warm, (termperaturewise) starts and runs. Any ideas?


    Bad CDI they can be temperature sensitive just like a vehicle

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