15 Kawasaki - need advice on problem.

Discussion in 'Mechanic and Repair' started by Jason Pallas, Jul 17, 2005.

  1. Jason Pallas

    Jason Pallas LawnSite Bronze Member
    Posts: 1,325

    Has anyone else experienced a "miss" with their 15 hp Kawasaki twin. It seems like every so often, we'll get one that seems to develop a slight misfire. It usually passes within a few minutes - but I have seen it last for 10 -15 minutes. It seems like either an ignition problem or a fuel delivery problem. We tried putting a higher temp spark plug in them and that seemed to work for a while (thought we had it solved - but then we starting seeing the problem again last week - may have been heat related as it was above 95 every day). Please share any similar experiences with me / possible rememedies. I'm a pretty damm good mechanic - but before I really delve into this one, I'd like to get some other input/experience (in case this is a common prob that I haven't heard of). Thanks in advance to all my buds in the mechanic forum.
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    A sure fire test (lol) would be to catch the engine when it's acting up and throw a spark tester on the plugs, This will tell you if it is infact a ignition coil acting up. That would be my guess, Then when the problem is solved go back to the factory specified heat range plug.
     
  3. sildoc

    sildoc LawnSite Silver Member
    Posts: 2,925

    I have had a mis on my kawi 15 hp several times. I do not belive it was an actual mis but dieseling of the mower. ever time was 100 + degrees and I belive the fuel was near gas state as it entered the carb. You will notice it sputter when you turn it off.
     
  4. PTP

    PTP LawnSite Bronze Member
    from Tulsa
    Posts: 1,383

    If this is in fact the case, try using higher octane fuel. This will solve the problem. The higher octane does not detonate (what you called "dieseling") as easily.
     
  5. Jason Pallas

    Jason Pallas LawnSite Bronze Member
    Posts: 1,325

    restrorob - I agree. The problem is that I believe the plug is in fact firing (because it does'nt sound or feel the same as if one of the cylinders is completely gone). BUT, I think the plug is missing about 30-50% of the time. If I disconnect one of the spark plug leads, the drop is much more than the "miss" that I'm describing. I'm relatively certain that the ignition system on these machines are clean (no inadvertent grounds, etc...). So, I'm not sure a spark test would actually catch the problem/troubleshoot it correctly. Any other suggestions. I am going to try a higher octane fuel (although it doesn't exhibit any other signs of dieseling. More input / other suggestions greatly appreciated'
     
  6. sildoc

    sildoc LawnSite Silver Member
    Posts: 2,925

    Yes. changed plugs and went to a 92 octane fuel during the high temp months. Although talking to kawi you should not need but 86 octane. Hey I will spend the few pennies to have a better running machine.
     
  7. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    A spark tester doesn't only show you a no spark problem but also shows a intermitting spark and a weak spark also. A engine can run on a weak spark but it will not run properly as you described, It could be a coil breaking down under high heat conditions.
    It was just a suggestion.
     
  8. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    The next time the described situation develops, pull one spark plug wire. If the engine continues to run, replace that wire and pull the other wire. If the engine dies when either wire is pulledm more than likely you could have a valve hanging up. In my case it was an exhaust valve that had carbon build up on the stem. Just something to consider.
     

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