kohler ch740 please help

Discussion in 'Mechanic and Repair' started by allis41, Sep 21, 2013.

  1. allis41

    allis41 LawnSite Member
    Posts: 2

    I have a exmark with a kohler sp27 on it have owned mower for 3 years ran great until this spring. It started to miss on and off. have ran it all summer like this. at first start up it would run good then miss for a few seconds to a min or two then run fine again would do this for about 30 min or so then run fine the rest of the day. if I was running the mower everyday after a day or two it wouldn't do it at all but if the mower sits for a couple days it gets worse. the one plug looks good the other is all black and carboned I thought it might be a lifter bad. it finaly bent a pushrod on the side with the black plug. I replaced the lifters the pushrod and took head off removed vaives checked the seats and they are tight cleaned valves and reinstalled with new head gasket. started engine back up no good. compression on cylinders are 130 and 135 seems good. spark seems good changed fuel filter. it doesn't have a completely dead cylinder cause it runs if I pull the wires off the plugs one side at a time but it is like it is missing it last little bit of power it needs. as soon as I engage the pto it dies it has 1023 hours I am out of ideas I need help. it ran good until it sat over the winter and started acting up this spring is it fuel related or inside the motor somewhere HELP
     
  2. MJB

    MJB LawnSite Silver Member
    from Wa
    Posts: 2,869

    Are you sure 1 of the coils is not acting up? Sometimes a coil goes bad fast some times they take a while. I would change the 1 on the bad side .
     
  3. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,533

    I learned with coils to change in pairs. If one goes the other ain't far behind. Even on vehicles I upgraded all the coil packs.
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  4. MJB

    MJB LawnSite Silver Member
    from Wa
    Posts: 2,869

    I aggree 100% I just was not sure if that was the issue so didnt suggest both.
     
  5. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,533

    Coils seem to be a universal problem with engines lately. I don't know if its Chiba quality or what, but I've changed more in the last 3 years than than 25 combined.
    Posted via Mobile Device
     
  6. MJB

    MJB LawnSite Silver Member
    from Wa
    Posts: 2,869

    Ive noticed that with both Kohler and Kawasaki I rarely get to 1000 hrs without replacing the coils on engines that were built since 2010. My older mowers never seemed to have coil issues that often.
     
  7. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Posts: 727

    Amen to that!

    It's no secret that they have had problems with coils! With Kohler, it was all good before they decided to go to DSAI (powered) coils. Then they had "some problems" and revised them... Then they had some failure rates "higher than expected" on the revised coils and revised it again...

    Then one day this spring in Kohler Wisconsin the clouds parted, and a voice from above seemed to say "Look, you idiots, go back to the old MDI coils that actually worked"!... So they did!

    Depending what Spec. number your engine is and what version coil you have is depends on which kit you need! If it is concluded that the coil(s) are at fault and not a fuel issue...
     

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