Help adjusting RPM's

Discussion in 'Mechanic and Repair' started by Ridin' Green, Jul 26, 2013.

  1. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,364

    I need a little advise on adjusting my Kawi's RPM's. Please, only replies from those who actually know the correct way to do this.

    I have a Deere Z950 with the FX850. I just mounted a tach today, and it shows I'm holding steady at around 3570-3580 at WOT off load. With the deck engaged I'm holding right between 3450-3480. I know there's a way to adjust this from all the reading I've done on this sight, and I've also read that someone here has posted either diagrams or actual pictures on how to adjust the RPM's correctly.

    I want to have the RPM's in the 3580-3600 range or so with the blades engaged. Thanks in advance. I appreciate any help I can get.
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Me know no-ting......


    [​IMG]
     
  3. JCLawn and more

    JCLawn and more LawnSite Fanatic
    from MI
    Posts: 5,206

    What's you reason for wanting close to 19,000 fpm? Just curious
     
  4. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,364

    Excellent. I knew one of the gurus in this forum could help. Thanks a ton bro!!
     
  5. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,364

    Where'd you come up with that figure? Unless you now for sure that the PTO pulley is the exact same diameter as the spindle pulleys, there's no way to know for sure what the BTS in FPM will be. I will measure them both tomorrow to see, but I'm pretty certain they are different diameters.

    I'm not trying to do anything more than get it back to where it is supposed to operate. The last few hundred RPM's of any brand engine on any Z is the range that is most responsible for producing the best QOC. I need to get those RPM's back where they should be at to eliminate the stragglers I am getting lately that weren't there before the dealer "adjusted" it downward from where it was when new. I don't know what all they did to it, but at full sticks it is now slower as well.
     
  6. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,364

    I measured the PTO pulley, and then the spindle pulleys. The PTO pulley needs to revolve 1.11 times to make the spindle pulley revolve once, so basically 10% more times per revolution. That, along with all the other math, makes the BTS in FPM much less than 18K, and nowhere near 19K, when the engine is turning 3450 on load. This is why I want to bump it up to where it should be turning the BTS as advertised at 18K FPM.
     
  7. JCLawn and more

    JCLawn and more LawnSite Fanatic
    from MI
    Posts: 5,206

    You need to cut back on the coffee haha or get more work
     
  8. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,364

    Why, because I know how to do math, and want my mower to operate as designed?:confused:
    I've been working plenty, believe me. Lots of construction mixed with mowing and other lawn care work. I'm good I think. Could use another cup of coffee though.:)
     
  9. JCLawn and more

    JCLawn and more LawnSite Fanatic
    from MI
    Posts: 5,206

    Because you have been thinking about this wayyyyyyy to long haha
     
  10. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,364

    Probably so, but I like things RIGHT;):laugh:
     

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