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Kawasaki FC420V won't run under load

Discussion in 'Mechanic and Repair' started by derekmman, Feb 11, 2008.

  1. derekmman

    derekmman LawnSite Member
    Messages: 12

    First off just wanted to say I am new to this website and I was blown away by everyones quick responses and knowledge on the topics. With that said here is my problem, I have a Lesco Commerical W.B. w/ a Kawasaki FC420V engine on it.

    The Problem:
    -It will die immediately once a load is applied to it.
    -Will die if throttled up too quickly, it must be babied up but once there it will evenually die (within the minute, plus this is also w/ no load).
    -But on the good note it will sit there and idle all day long.

    What I have done so far:
    -Replaced the fuel filter and hose.
    -Cleaned the carb, making sure all orfices were clear.
    -Checked the spark plug just to knock that off the list.

    What I have noticed:
    -It will backfire when dying, sometimes.
    -The butterfly valve on the carb will be thrown wide open right as it starts to die by the arm in the picture.
    Any help would be welcomed.

    Thanks in advance,
  2. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    Hey Derekmman, lets start with easy things to check remove you gas cap and with the mower still, look inside the tank(bright flashlight) for any debris that may be blocking the outlet from the tank into the 90deg. on/off valve fitting.
    If this looks clear(reinstall your gas cap) grab a clean jar or empty gas can and shut off the fuel then disconnect the line at the carb and insert the end of the line into the jar/can and reopen the valve and see how your flow looks, should be nice and steady if not check back from this point into the tank for any obstructions.

    Post back and let me know what you find, or don't find:laugh:
  3. derekmman

    derekmman LawnSite Member
    Messages: 12

    It has a nice steady flow of fuel. I got to playing with the throttly by manually moving it and any sudden movements will result in the engine dying.
  4. lifetree

    lifetree LawnSite Fanatic
    Messages: 5,369

    That was a fast response, only 22 minutes after he ex[plained what to check ... or, had you already checked those items ??
  5. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    ok good, now you said that you have cleaned the carb. Did you completely remove and tear down or just spray carb spray up the center?
  6. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    This is usually from a blockage or restriction in the transition ports on the carb, when you go from idle to full rpms the carb adds extra fuel from these ports to help with the extra fuel requirements of full rpms or any type of parasitic load. This is why I asked what type of carb cleaning you had performed.
  7. Landrus2

    Landrus2 LawnSite Fanatic
    Messages: 5,021

    We always over look the governor.
  8. derekmman

    derekmman LawnSite Member
    Messages: 12

    Cleaning the carb pretty much consisted of taking it off the engine removing the bowl and spraying up into the holes and watching it come out the other side. I was/am hesitate on taking it completely apart. I have flashbacks of the first time I took apart carb, but mowers carb is alittle less involved, I hope.

    Lifetree, I had already checked those things but ran back outside to double check.
  9. derekmman

    derekmman LawnSite Member
    Messages: 12

    So what you are saying is those ports, I am guessing the smaller ones to the sides, might be clogged and that I should tear it all the way down and clean it?
  10. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    I wish it was that easy:laugh:
    this is a link to a breakdown of your carb

    you need to pull out from the carb ref# 11003 and make sure its clear, also you will need to pull out ref#49123/A and ref#49121/A(be careful they are soft brass)and make sure all the small passage ways are all clear and free of debris. You will also need to remove ref# 92009c and pull out ref#92064/A and clean out here also. With all the jets removed you can easily clean with a can of carb spray and compressed air. It may be in your best interest to take the carb to a shop and have it stripped and cold acid dipped and rebuilt. But that is only if you are unsure of the rebuild process.

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