Discussion in 'Mechanic and Repair' started by Gmgbo, Mar 14, 2008.

  1. Gmgbo

    Gmgbo LawnSite Senior Member
    Messages: 382

    I recently bought a 1987 othale sweeper model 54hl. It has a bad 24hp onan engine. Does anyone know if I can replace it with another kind of engine, and if so which 1?

  2. Jay Ray

    Jay Ray LawnSite Fanatic
    Messages: 6,510

    I'm assuming the Onan is probably a horizontal, but not sure about that. Smallenginewarehouse does not list a repower engine for any Olathe. But you can email then with all the ID numbers (engine and machine) and ask them. So this is a stab in the dark.

    If it is horizontal you might find something with the same size and length side shaft, but the shaft sits lower than the Onan. It's unlikely finding something that is just like the Onan.

    Then you can make a spacer plate to bring the side shaft up to the original Onan shaft height. Tack weld the plate in place, determine where the new engine should sit on the plate to put the shaft in the same place as the Onan shaft was. Then determine the locations of the new mounting holes (hopefully just scribe thru from the top), remove engine, and drill thru the plate and the frame. If it is going make a partial hole in the original holes you want to change to a fairly flat pointed bit once you are almost thru the spacer plate.

    Of course this assumes the new engine fits in the available space. And it is sure easier to talk it than do it.

    Or it might be easier mounting right to the frame if you can determine the original or a different size belt will work. A 60" flexible sewing tape can help a lot in sizing for a belt.

    If it has couplings the work will have to be more accurate and the motor shimmed and pinned. Needs to be dialed in.

    Then there is maybe piping the exhaust and the electrics to deal with.

    Maybe you got yourself a good project. Hope you can find something that just bolts right in though.
  3. JJS

    JJS LawnSite Senior Member
    Messages: 334

    I replaced the engine on mine with an Onan performer 20 so you can still find the ideal onan engine.
  4. Gmgbo

    Gmgbo LawnSite Senior Member
    Messages: 382

    I bought a 24 hp honda replacement from small engine warehouse with electric start and an oil cooler. They also had a flywheel adapter that I purchased. Hopefully i will have it on today, I just have to raise the engine about 2.5 inches. Ill post pics.
  5. Gmgbo

    Gmgbo LawnSite Senior Member
    Messages: 382

    Old onan engine

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  6. Gmgbo

    Gmgbo LawnSite Senior Member
    Messages: 382

    new honda 24 hp

    misc 069.jpg

    misc 073.jpg

    misc 071.jpg
  7. GravelyNut

    GravelyNut LawnSite Bronze Member
    Messages: 1,594

    Onan stopped making those a number of years ago. And parts for them are becoming harder to find and more expensive. The last Onans were made in Canada by Linamar. Later Onans are really Subaru/Robin engines. Any new engines you get that say Onan Performer are NOS items.

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