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Rotzilla's avatar
Rotzilla
Explorer
Feb 26, 2014

Onan 4000 not starting

Purchased new with TH in late 2013, and is still under warranty, however I attempting to eliminate non-genset possibilities before taking it in.
I have been running it monthly as recommended, 30 days ago it ran without incident, however it will not start now.
Its throwing a code 36, failure to shutdown properly, error possibilities according to the manual are; low fuel, spark plug, battery, air filter. All the above have been checked, and all electrical connections have been cleaned. The last shutdown was without issues.
When attempting to start, the starter button flashes and the solenoid clicks, but the starter does not turn over. I have 11.5 volts to the genset side of the solenoid, and the battery is fully charged and brand new.
Does anyone have experience with similar problems or know of something else I could check before taking it out of hibernation and dragging it 20 miles???

7 Replies

  • Update, ready to be picked up. Tech said the starter motor had failed.
    Hopefully no further issues.
  • Make sure it isn't "stuck under compression". I am not sure if they differ by model, but on my Onan 4000 Microquiet I stuck my hand in on the left-hand side and felt around for the fan blades on the end of the flywheel. I couldn't move the blades by hand (you should be able to turn them).

    If that is the case, take a 9/16" socket/wrench and a small breaker bar and gently break it loose.

    http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27068139.cfm
  • Check for a loose or corroded ground at the generator and the battery. A bad ground will show some continuity, but will not be able to carry much current when you have a high demand device ( starter ) wanting power.
  • Battery is 12.5v, the 11.5v reading is taken from the starter side of the solenoid while the start button is being depressed. The shop says the genset should start as long as the votage is more than 10v.
    I even tried the boost/start function on my battery charger, it made no difference, just a click and flashing starter switch.
  • Bad battery, poor connections, solenoid has failed, has poor ground.
  • Check the voltage at the battery. I believe 12 is considered dead.

    I would think your voltage reading at the generator should be above 12.5 if the battery is healthy.