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bob_b1's avatar
bob_b1
Explorer
Jun 16, 2014

Onan generator caught fire today.

My generator started to catch fire today. Luckily I was outside the motorhome when it happened. I was breaking camp, unplugged from the pole and turned on the generator as I've a hundred times. Everything was fine for the next ten minutes. I heard the motor labor really hard, return to normal and then was laboring harder. I looked over and saw a massive cloud of smoke coming from under the coach. I ran in and hit the stop button. I can only imagine what would have happened if I wasn't right there:S

It smelled like burnt transmission fluid. I never looked at generator when it was running so I don't know what was happening. Just looking at afterwards gave me no clue. It was still producing power because the air conditioner was running. I didn't bother to look at the voltage because shutting it off was my only priority.

It is a 22yr-old propane powered Onan Maquis 6500 with 1200 hours on it. I haven't had to replace any parts on it for the last five years. The oil was changed recently, but that's all that I've done with it.

I've been on this forum a long time and have never heard of this happening.

What do you make of it?
Class A
  • J-Rooster's avatar
    J-Rooster
    Explorer
    Jun 24, 2014
    I'm sorry to hear about your genset! Another possibility could have been a rodents nest on the back side of your generator, and the nesting material caught on fire from the heat!
  • bob_b1's avatar
    bob_b1
    Explorer
    Jun 24, 2014
    I bought a Honda EU3000is instead of fixing the Onan. I've been wanting an excuse to buy one for some time now. I'll mount it on the back of the motorhome and continue to enjoy life:)
  • zman-az's avatar
    zman-az
    Explorer
    Jun 16, 2014
    Rented a houseboat a couple years ago and the Onan gas Generator started on fire. Was running for about 30min and died. Fired it back up and 5-10 min later I smelled burnt plastic. Looked outside to see the plastic cover on fire. Good thing we were on the lake as there was plenty of water although it was not needed as the fire ext did its job. It was a rental so we never knew what happened to it.
  • Pogoil's avatar
    Pogoil
    Explorer
    Jun 16, 2014
    Mine is a 95 6300 propane and when the time comes will rebuild it if I can. I really like it.
    Right now it runs well. No hour meter so hard to tell how many hours.
    Last week we ran it all day with both air cond. running.

    Pogoil.
  • jferre9570's avatar
    jferre9570
    Explorer
    Jun 16, 2014
    If I were in this situation (and I have a '95 vintage Onan Emerald Plus propane) I would look long and hard at a rebuild. The last time I thought I was going to have to make the same decision, I found the new ones to be bigger (wouldn't fit) and are higher RPM. Also, as near as I can tell, the only differences between the gas and propane models are the propane regulator, intake, and (if liquid fueled) the preheater on the exhaust, so using your parts to convert a good condition gas might be an option.
  • gemert's avatar
    gemert
    Explorer
    Jun 16, 2014
    inky wrote:
    If you are going to purchase a new generator, be prepared to shell out some bug bucks for that size. You will be in the $5,0000 range plus install. Used LP's are almost none to be had. You can find a few used gasoline models around. I am going through a problem with my 23 year old LP generator. I have checked all the salvage yards around the country and LP fueled just are not available. I am having a rewind on my rotor and stator for about $700.00 plus labor. Mine runs good, just does not generate power.


    Can you buy a gas and have it converted? I don't know much about them but have been told that they will convert my portable generator. Just a thought.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Jun 16, 2014
    I too would suggest checking the transfer switch, epically if you were still connected to the park's pedestal at the time.. but...

    Most likely a winding shorted.. Little danger of a genuine fire (The generator should shut down for other reasons before that happens.. Possible to re-wind it, but... expensive no matter what the result.

    At 22 years. a new genny might not be a bad idea.
  • dougrainer's avatar
    dougrainer
    Nomad
    Jun 16, 2014
    Your 22 year old probably has the standard Rotor winding. It is not uncommon for those to smoke when they fail. get it to a good Onan shop and you CAN have the rotor rewound a lot cheaper than new. Onan will not offer it, but you can find a shop (motor/electrical winding shop) that can do it. Doug
  • hipower's avatar
    hipower
    Explorer
    Jun 16, 2014
    If replacement is the end result and you chose to seek a used or salvage unit don't be afraid to purchase a gas unit, if the price is attractive. LP conversions are not difficult or extremely expensive.

    Of course it may be an option to look for a diesel unit and make the conversion to your larger onboard fuel supply.
  • bob_b1's avatar
    bob_b1
    Explorer
    Jun 16, 2014
    Gjac wrote:
    Two things come to mine based on my experience. When my generator refused to start(no spark) I removed the top cover to get to the coil and underneath found a mouse nest of dried grass and other flammable materials. I could see where the acorn shells were charred. The second thing that comes to mind is an oil leak that drips on the hot exhaust. From your post you never saw flames only smoke, so if it is not electrical as others have said I would check for these 2 situations.


    That would be nice if that were to be the case. It did have a strong electrical or transmission fluid smell to it. I will buy a motorcycle jack and remove it from the motorhome, so that I can inspect it little better. I did see chipmunks running around all weekend. I just wonder...

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