Kawasaki FR691V dropping to many RPM's with load

Discussion in 'Mechanic and Repair' started by bighawk316, Nov 16, 2013.

  1. bighawk316

    bighawk316 LawnSite Member
    Posts: 7

    I have an Exmark Quest 50'' deck with the Kawasaki FR691V and it is set to run at 3600 RPM's with no load but when the blades are engaged the rpm's drop down to 3300 RPM's. Is this a normal drop in RPM's under load or should the drop in RPM's be like 100 to 150 RPM's? I am wondering if it could be a governor problem and if it is how would I go about adjusting it?

    Thanks In Advance For The Help,
    Bighawk316 :)
     
  2. twomancrew

    twomancrew LawnSite Senior Member
    Posts: 945

    How many hours on the unit? The compensating spring might have issues, but I doubt it. Maybe a stick or old grass is wadded up in the linkage? You sure your baseline is 3600? Is it really cold when you take your readings?
     
  3. bighawk316

    bighawk316 LawnSite Member
    Posts: 7

    30 hours on motor. I have a hour-meter / tachometer hooked up to the engine and the readings are taken after the motor is fully warmed up. How many rpm's should be lost under load?
     
  4. bighawk316

    bighawk316 LawnSite Member
    Posts: 7


    30 hours on motor. I have a hour-meter / tachometer hooked up to the engine and the readings are taken after the motor is fully warmed up. How many rpm's should be lost under load?
     
  5. twomancrew

    twomancrew LawnSite Senior Member
    Posts: 945

    I can't answer that for you. Does the motor seem fine under a load or does it not mow well anymore? Was this an all of the sudden issue?

    You can read aboutr the governor compensator spring and if you find it you can try moving the spring a hole closer to the pivot of the governor arm. If the motor starts to surge loaded or not then you can't run with that much compensation(have to move spring back out a hole). Try some lube to see if it helps, also 30 hours is still new so let it get good and broke in before going to crazy. Give it 100 hours then reset max running speed and clean and lube linkage to see if it improves. I think you might not have a problem at all, but I am not the one to say that- just to say it. I don't know for SURE.
     
  6. bighawk316

    bighawk316 LawnSite Member
    Posts: 7


    It seems to mow well until I get into thicker grass. That is why I was wondering if the rpm's should drop to 3300 rpm's when the blades are engaged. I will check on adjusting the spring in the governor arm. Thanks for replying
     
  7. twomancrew

    twomancrew LawnSite Senior Member
    Posts: 945

    Your welcome, I am pretty sure after more breaking in it will improve for you. I have bought brand new big mowers before too and it takes a good breaking in to get good performance. A 300 rpm drop aint bad on a new unit in my opinion. Opinion aint worth much.
     
  8. Exmark PR

    Exmark PR Sponsor
    Posts: 238

    The engine RPM in that unit is set up at 3300 RPM no load, not 3600 RPM. You should start by adjusting that and then check the engine RPM after engaging the blades. After engaging the blades, the RPM drop should be less than 100 RPM.
     
  9. bighawk316

    bighawk316 LawnSite Member
    Posts: 7


    I thought the Kawasaki FR691V was supposed to run at 3600 RPM's. My mistake and I will try to drop the RPM's down to 3300 RPM's and see what happens. My only concern is will my quality of cut suffer?
     
  10. twomancrew

    twomancrew LawnSite Senior Member
    Posts: 945

    Dull blades will be worse than the drop in rpm. Break it in good and keep the deck clean and blades sharp. It will do fine like it does for everyone else.:)
     

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