It's a Mystery - Recoil rips out your hand !!

Discussion in 'Mechanic and Repair' started by rob7233, May 19, 2010.

  1. rob7233

    rob7233 LawnSite Senior Member
    Posts: 861

    I have a 1996? Kawasaki FC420v -S09, 14HP engine w/ the ACR that has a history of hurting people and cutting their hands open from the pull cord suddenly ripping out your hands when pulling the recoil. This walkbehind has been a back up for years but recently, I needed to loan it out to a friend. Even with explicit warning and instruction to pull the cord slowly all the way out before trying to start it, he still got cut up.

    Last time I used it, it was running rich and the the plug was sooty black. Since then it has a new plug and a professional carb adjustment and pretty much starts on the first pull with a healthy tug. I now have the machine being looked by a quality shop where the folks there seem to know what they're doing and are familiar with this engine. This is what they checked so far:

    1) The mechanical ACR release works and lifts the valve as it supposed to.
    2) They have checked the valves and fine tuned the adjustment while they were there(nothing unusual noted).
    3) The engine still seems a little harder to pull than normal (Could it be too much compression??) Now this has been typical for it..
    4)They are doing a compression check on it now
    5) The shop has even called Kawasaki and asked if there was something else they could do or look for -- Kawasaki's reply was to "just pull harder" WTF?!!

    Could this be from a buildup in carbon? I've run seafoam thru it in the past and didn't see any change in recoil resistance. I know I've had "running on" issues with it in the past especially when it got hot from use. However, it hasn't done that since the Seafoam. Should I try the LMT -Lawn mower tuneup by Blaster? It does do a good job at removing carbon.

    Now I'm just guessing what might be the problem. It's still a mystery.
    Does anybody have any suggestions or clues to the problem? :confused:
  2. rob7233

    rob7233 LawnSite Senior Member
    Posts: 861

    Also, just to let you know, the shop also checked the flywheel key for shear which would effect the timing. All of that is okay.
  3. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,245

    The ACR has play in it. It works when it wants to. Change the cam.
    Slight flooding of the carb might cause it to kickback, but if this has been an issue for a few years, its probably not the problem.
  4. rob7233

    rob7233 LawnSite Senior Member
    Posts: 861

    Does anyone know according to Kawasaki what the compression reading range would be, with an activated ACR on this engine?
  5. rob7233

    rob7233 LawnSite Senior Member
    Posts: 861

    Since the ACR operates via a pin on the camshaft, unless it's worn, why would it operate only some of the time?
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    The pin is activated by a spring loaded flyweight on the cam, The spring can weaken or break causing intermittent ACR operation.

    They should Ohm test the coil and igniter, Either could be out of proper spec range and cause hard starting at cranking rpms but run fine at higher rpms.

    I didn't see your post before the PM......
  7. carlriv

    carlriv LawnSite Member
    from Mass
    Posts: 99

    Years ago I had one of those, and I think it was repaird with a new camshaft... I think it was worn. The cord pulled out of my hand so hard that my wrist hurt for months.
  8. rob7233

    rob7233 LawnSite Senior Member
    Posts: 861

    The compression reading with the ACR was 90. I was told that it could be considered in the normal range. Is it?

    Any idea what a camshaft replacement would cost(parts & labor) ?
  9. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,245

    Its cheaper to muzzle the dog than to pay for the bite.
  10. rob7233

    rob7233 LawnSite Senior Member
    Posts: 861

    Well, Kawasaki has been called and their advice was: " it seems that you've check for everything so just pull harder" Now, that answer is just choice.

    BTW: P/S I have a good idea what a camshaft repair would be but the shop states that the ACR is working each and every time. I just don't throw parts at anything unless I have clear evidence it's needed, neither does the mechanic.

    What would the normal compression/PSI range be for this engine with and w/o ACR ?

    How far out should the rocker push the rod out to activate the ACR?
    Does anyone have the spec(s)?

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