Koher 20 hp engine trouble

Discussion in 'Mechanic and Repair' started by mcambrose, Nov 19, 2007.

  1. mcambrose

    mcambrose LawnSite Senior Member
    Messages: 518

    I have a 20 hp kohler with 900 hours. It has been using oil for a while. I noticed that there was a small leak at the OHV cover just about the spark plug. Yesterday it would not start, so I checked the carburetor to make sure the fuel pump was working. It was okay. I then looked at spark plugs. The front plug was totally gummed up around the outside of the plug around the fins of the cylinder. I replaced plug and it still wouldn't start. A couple of times it backfired while I was trying to start it. I checked the compression and found the bad cylinder to be 120 psi and 150 psi on the other cylinder. If I try to start it, it will hit every once in a while but just cant get started. Any suggestions.
  2. Two Seasons

    Two Seasons LawnSite Senior Member
    Messages: 791

    Flywheel key sheared off?
  3. mcambrose

    mcambrose LawnSite Senior Member
    Messages: 518

    I checked the firing and found that it would fire intermittently on both cylinders. I called the Walker technician and he suggested that the circuit breaker on the instrument panel could be causing the problem. I had a 5 amp CB in my Walker and they have upgraded to a 7 amp. He said a 10 amp would also be ok. I switched one out of my 2003 walker and it started immediately and ran good. This won't fix the oil burning and compression problem, but at least I know it is worth putting rings in. Thanks for the response I received. The response was a good diagnosis based on the facts that I had entered.
  4. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    That 5AMP to 7AMP upgrade on the circuit breaker was in a service bulletin. What happened was the motor for the Grass-Pak system in the hopper is on that circuit. In most of the cases the engine ran just fine until the Grass-Pak system was turned on. Then the breaker did not trip right away it heated up very slowly and would trip without popping out so when you looked at it you could not tell it had tripped.

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