Plugs 1 Foul 1 Fine

Discussion in 'Mechanic and Repair' started by Atlantic Lawn, Nov 13, 2002.

  1. Atlantic Lawn

    Atlantic Lawn LawnSite Senior Member
    Male, from Outer Banks NC
    Posts: 940

    I have a Kawi 15 twin less than 200 hrs on it. The other day it had a lot less power and wouldn't rev up right. Sputtering so to speak. Never happened before. I used another mower that day and pulled the plugs that night. One was oil/gas fouled the other looked like it had run a bit hot. The mower was only run for about two mins before it was shut down. Changed the plugs and it started and ran fine. Haven't cut all day with it yet. Any thoughts on what has occured here ? Thanks Guys
     
  2. Was there oil and gas on the plug, or just one or the other?
    If it was just gas I would suspect a bad plug and nothing else to worry about.
    If there was oil you could have a bad ring or a valve problem. Also could have been a piece of carbon that caused a temporary problem until it disintegrated.
    If it is running fine with new plug I would guess no serious problem but would do a compression test on that cylinder just to check.
     
  3. SWD

    SWD LawnSite Senior Member
    Posts: 989

    Some of the larger twins have automatic compression relief systems to aid in starting. I have experienced similar problems with manual, pull start, twins where-in one plug fouls and one does not. I like the idea of a compression check, but do a cold and warm one. Then try a leak down test. The last thing I would do would be to run a higher octane fuel for three or four tanks in addition to a additive solely as a clean out method.
     

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