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another kohler 25 issue, weird! ch-25s

Discussion in 'Mechanic and Repair' started by SILVERSTREAK INC, May 9, 2013.


    SILVERSTREAK INC LawnSite Senior Member
    Messages: 295

    kohler on my brothers scag started running bad, by the time he drive it back to the trailer im guessing it was running on one cylinder, he cracked the #1 head

    put a new head on, now both cylinders have 130-150 psi

    will only spark on one cylinder at a time!!!!!!!!!!!!

    start it up with only #1 plug wire connected, it runs poorly (same as before the head cracked) start it up with only #2 plug wire wire connected it will run poorly

    connect both wires and start, it runs poorly, disconnect #2 wire while running and NO change in how it runs, reconnect while running and pull the other side, it will either die if rpms are low or if rpms are high will pop sputter and continue running poorly

    checked air gap, new plugs, checked coil resistance & swapped coils to other sides, same exact cylinder symptoms so rules out coils, figured it was exciter wire on the #2 side, put a new from dealer smart box on it, same thing! both plugs have enough spark with the spark tester

    fed up with this thing, does anyone have ideas? i have the manual
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    What's the spec and serial numbers ?
  3. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,329

    Normal compression is 180...
    Kohler 25s use 3 different ignition systems....
    Like RestroRob said....need some numbers..

    SILVERSTREAK INC LawnSite Senior Member
    Messages: 295

    ...... the new side has 150, now after checking it again the old side has 30psi, blew 100psi air into the cylinder and it is coming out of the lifter area, so im guessing now the other head cracked, crazy because before taking the "bad" head off i swear it had 130psi compression

    oh well but thanks

    spark check is fine in both cylinders
  5. herler

    herler LawnSite Fanatic
    Messages: 5,139

    Some days, things just don't go our way.
    I have had them days.

    Good luck

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