KAW FC420V constant hunting/surging

Discussion in 'Mechanic and Repair' started by dialupsux, Jul 17, 2008.

  1. dialupsux

    dialupsux LawnSite Member
    Messages: 1

    I have a FC420V -hso6 on a Bobcat Walkbehind. Under load it runs ok with very little surging, but take off the load and it surges like crazy.I have blown out the carb with air and put in a new sparkplug. Also I have noticed that the shaft on the carb that is closest to the cylinder (the one that connects to the govenor) rattles like crazy,like it is loose.So here are my questions:

    1 - Is this just a dirty carb or could it be governor related or possibly could it be carbon buildup on cylinder head which I have not checked or cleaned since it was new (7 years or so)
    2 - I looked for a new carb on J Thomas but they dont offer the carb as far as I can tell, so who sells them ?
    3 - I understand the FC420V is discontinued and the new version is a "KAI" type engine,about 800$, how are these newer engines,any problems?
  2. Lawn-Sharks

    Lawn-Sharks LawnSite Senior Member
    Messages: 912

    My Gravely has the same engine and had the same problem after i had to make a quick fix one time by simply bypassing a leaky fuel filter and it got trash in the carb and i have since replaced the filter and still have had to clean out the carb 4-5 times since because of trash in the lines, it runs better now but from time to time it shows it ass and i have to clean it
  3. jkason

    jkason LawnSite Senior Member
    Messages: 546

    If the throttle shaft is loose - it's worn, and it's time to replace it. (Easier to do the whole carb.)

    If the carb is NLA, you are SOL (unless someone has NOS).

    The KAIs are the "latest and greatest" from Kawi, no problems so far.....

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