Kohler 18HP on SCAG won't turn over when hot

Discussion in 'Mechanic and Repair' started by MEADWOOD, Feb 11, 2008.


    MEADWOOD LawnSite Member
    Messages: 1

    I picked up an older ST18KH SCAG rider with a 61 inch deck. When I try to start it after it has run awhile (hot) the key will not cause the starter to turn over. If I wiggle controls and key it will click, and eventually will turn over and start. I wired a bypass switch to take the safety's out of the picture (thinking it was the neutral detector) but still no good. I initially replaced the battery. I also tried shorting out the key terminals but determined the key switch was probably good. The solenoid is mounted under the battery, separate from the starter motor. Someone said that it could be the starter motor bushings. Any comments on how to diagnose if it is the starter or solenoid, or something else? Thanks
  2. mowermankevin

    mowermankevin LawnSite Senior Member
    Messages: 270

    First off, you did right trying to isolate the circuit problem, try this: run a jumper from a good battery (+ to+) and a good ground from both in other words a separate battery, touch the hot(+) from the good battery to the big post on the good battery to the red,center post of the starter and see if it fires the engine, if it does,its a safety or ignition switch, if it still doesn't crank it's a starter, solenoid problem,let us know what you come up with,O.K.?
  3. GravelyNut

    GravelyNut LawnSite Bronze Member
    Messages: 1,594

    More common for the solenoid to go out than the starter itself. The contact area of the soleniod tends to build up an oxide over time with use. Each use burns it a little and at some point they start acting flaky.
  4. sawman65

    sawman65 LawnSite Senior Member
    Messages: 754

    is this a magnum engine or comand?
  5. Landrus2

    Landrus2 LawnSite Fanatic
    Messages: 5,050

    ST18KH SCAG :drinkup::drinkup::drinkup:
  6. Two Seasons

    Two Seasons LawnSite Senior Member
    Messages: 791

    I'd clean out the solenoid area first and lube with Kohler grease. If that isn't the problem, replace the starter.

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