Engine RPM Pulsing

Discussion in 'Mechanic and Repair' started by lawnandl, Sep 22, 2006.

  1. lawnandl

    lawnandl LawnSite Member
    Messages: 78

    Does anyone know why an engine pulses. The rpm's are going up and down quickly. It is a 12.5 Kawasaki engine. It's very annoying, and I'd like to see if I can get some advice from you guys out there, Thanks
  2. Jim@MilkyWay

    Jim@MilkyWay LawnSite Senior Member
    Messages: 472

    That would be either the governor, most likely, or possibly a problem with the throttle plate, such as loose screws.
    If engine surge is rhythmical, then it would almost assuredly be governor. One of these guys will respond with adjust procedure
  3. khouse

    khouse LawnSite Bronze Member
    Messages: 1,465

    most likely cause is loose throttle linkage from the governor arm to carb. if there is any play in the arm and or the antisurge spring is missing then you'll get surging.
  4. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Perform this test;

    Start the engine and set the throttle to where it pulses, Then grab the choke linkage from the throttle control plate to the choke shaft on the carb. and SLOWLY start applying the choke.
    If it smooths out remove the carb. tear it down and blow through ALL ports and passages with carb. & choke spray cleaner paying attention to the main jet. Follow with compressed air if available. Check tank for trash, Flush fuel line and replace fuel filter.

    Just in case you need it;


    If the engine doesn't smooth out when applying choke then check your governor adjustment as listed below;

    Good Luck....

    Kawi 460 Gov. Adj..jpg
  5. lawnandl

    lawnandl LawnSite Member
    Messages: 78

    Thank You very much. I will experiment with this and let you know during the upcoming week. Thanks Again !!!!
  6. GearHead_1

    GearHead_1 LawnSite Member
    from Utah
    Messages: 34

    Restrorob's advice is a very well thought out post. I would certainly look at the carb or even suspect bad gas (water in it), if not these check O.K. then move on to the governor and it's adjustment.
  7. stumper1620

    stumper1620 LawnSite Bronze Member
    Messages: 1,889

    Is this at idle or full throttle?
    1 bad spark plug will cause this problem also.

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