Black plugs on kawasaki eng.

Discussion in 'Mechanic and Repair' started by kevin55rc, Feb 20, 2003.

  1. kevin55rc

    kevin55rc LawnSite Member
    Messages: 23

    Black spark plugs on all new units put into field, they all foul between 25 and 75 hrs, no matter the customer and or brand of mower. I was at kaw service school this year in grand rapids and they had 4 tech's there that said " Gosh i dont know". I hate to rejet cause they run so smooth at top end and DONT surge. Ideas??????? bpr5es are the plugs used and are correct in heat range. air filters and top no load speed are mint. alcohol free fuel, what do you all think???
  2. mower17

    mower17 LawnSite Member
    from la
    Messages: 26

    Are you sure the fuel mixture is correct. Many engines will sound great on choke even when warmed up but they are still running rich. You could replace the plugs with a higher operating temperature plug in an attemp to get higher temeratures to help burn the carbon or what ever is fouling them.
  3. kevin55rc

    kevin55rc LawnSite Member
    Messages: 23

    Hi there mower17, thats the problem........i cant verify with kaw the correct fuel air mixture { and yes the choke is not closed or partially closed } changing heat range of plugs is not the cure, what is making the plugs black-sooty in the first place is a mystery. This is on our 14 hp units all the way up to the 23 vert. If they spec'd the plugs wrong on all of their engines, ngk and kaw will not admit to it. my guess is a jet change is the way to go, but i do not want to create a surge problem at all. we are in a cold climate.
  4. Mr.Wrench

    Mr.Wrench LawnSite Member
    from N.H.
    Messages: 65

    Kevin, there have been a ton of rich running problems with the Kawi twins. There is a bulletin out for this problem if the engine falls into a certain serial number. We found that on some of the Kawi twins that the yellow breather tube that hangs down off the carburetor is to long and won't let the carburetor breath properly. We experienced this after we had to update the exhausts on all our Exmark Lazer Hp machines. Shortening and routing the vent tube away from the muffler cured the Rich and eratic running problem. The carburetors on the Kawis have fixed main jets, The only way we were told by Kawi to change them was to change the complete carburetor as per the bulletin.

    PS there was also a change to the intake gaskets and the spacer as well.
  5. kevin55rc

    kevin55rc LawnSite Member
    Messages: 23

    Thank you mr wrench on the reminder of the yellow vent tube !!!! I forgot about this "quick" glossed-over fact/forum at our last kaw update seminar !!! I will check our stock

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