Forum Discussion

gonesouth's avatar
gonesouth
Explorer
Oct 22, 2017

Generator Advice

I am looking at a 98 class A with a 10kw Onan diesel Generator. Seller reports that the generator "turns over but does not start". I had a similar 10KW Onan in my 98 Beaver Marquis and it did something similar (turned over with the starter but wouldn't fire) so I took it to a Cummins/Onan Coach Care shop. They diagnosed it as dead, needs replacement. (Something to do with the stator windings, IIRC)

Is that likely the diagnosis for this one, too? Or is there some other likely possible fault that would be easier to repair?

On three coaches I've used the generator for a total of about 8 hours of generating and maybe 60 hours of exercising, so it's not a big problem if it's a boat anchor, but if it's likely gone that should affect the price.

Thanks
  • could be that, could be fuel system, spark plug. if you have the skills and tools start digging otherwise its off to service provider. good luck. and I'd rather have it working and not need it than the other way around.
  • rk911: I doubt it is a spark plug problem. DIESEL!!!!

    Moisheh
  • moisheh wrote:
    rk911: I doubt it is a spark plug problem. DIESEL!!!!

    Moisheh
    fine. the point is it could be all sorts of things and the OP won't know until someone with the skills and knowledge...the OP or someone else...looks at it. had a buddy who bought a second-hand lawn mower from a guy who said it wouldn't start and considered it a lost cause. my buddy 'stole' it for a song, took it home and had it running in less than half an hour. bad spark plug.
  • rk911 wrote:
    moisheh wrote:
    rk911: I doubt it is a spark plug problem. DIESEL!!!!

    Moisheh
    fine. the point is it could be all sorts of things and the OP won't know until someone with the skills and knowledge...the OP or someone else...looks at it. had a buddy who bought a second-hand lawn mower from a guy who said it wouldn't start and considered it a lost cause. my buddy 'stole' it for a song, took it home and had it running in less than half an hour. bad spark plug.


    Diesel has no spark plugs;; most likely either fuel bad fuel pump or bad control board
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Diesel you said.. I will assume a fuel issue.

    Bad windings it will either (Depending on how it starts)

    1: Not turn over (On some ONAN's the generator doubles as the starter)
    or 2: Will start, but soon as you release the start button it stops

    Same with low oil by the way

    Since yours is turning over... but not starting... I'm thinking Engine/Fuel issue. Still I'd be asking for at least a thousand dollar discount.
  • So, the key point is that there are possible causes that are low cost. so use it as a bargaining chip and expect it to be toast, but if I end up with it get someone with some small diesel experience to help me check it out. Thanks
  • Any diesel that cranks but does not fire and run has only two levels of possible issue as I have discovered in 60+ years of taking care of diesels of all sizes.

    Most likely is a fuel issue and the easiest is that a filter was changed and the system no bleed as necessary for the injectors to get to opening pressure. This is an easy fix if you know how to do it. There are other fuel system possibilities that may require part$.

    Less likely is a fault in the engine like a hung valve (real bad in any diesel) and as soon as the engine has to come apart, you are into money.

    If you do buy it, take it to a boat shop. Those people deal with miniature engines (from my point of view) all the time and maybe even that same one.

    Matt
  • I'd go with fuel also. Fuel pump, fuel filter or since it is a 98 fuel line cracked sucking air and no fuel. Is there any smoke out the exhaust, sign of fuel. If yes the glow plugs in cold air. Do you get the tell tale clicking of the pump before the starter engauges, sign fuel pump works and air in the line. Fuel filter total clog, old coach could be.

    LEN
  • Dont mistake fuel systems problems as being cheap for sure. Injectors and pump can be VERY exspensive.
    Also, dont trust that it turns over without seeing so for yourself.