MAX Engine RPMs

Discussion in 'Lawn Mowing' started by MS_SURVEYOR, Jun 6, 2010.


    MS_SURVEYOR LawnSite Bronze Member
    Messages: 1,002

    We had a thread about RPMs up or down at shutoff. That seemed to be mixed opinions. But in going back to my Kohler manual, and talking to a Kohler engineer a couple of weeks ago, I was wondering what are your thoughts about max RPMs? For a year now I've been running my Kohler 30 hp (CV17-750) at 3600 rpm. The Kohler manual reads 3750 rpm no load, and the Kohler engineer said all CV17-750's leave the factory set at 3750 rpm no load. So I adjusted my rpm's at 3750 yesterday. What a big difference it made. I've been working out of town for the past 2 weeks, and my Bahia was at least 8 inches high. What a different engine and mower at 3750 rpm. I was able to mow at a greater speed without bogging down rpm's no lower than 3590. This is a big difference for me, because I have 5 acres of the grass. I did make an adjustment on the deck pitch by having 8 psi in the front tires, and 14 psi in the rear. For the first time ever I able to run at quicker speeds without bogging down, and not having any stragglers left behind. Now I need to measure my deck pitch at the 8/14 psi. Drop my pressures to 8 psi front, and 8 psi rear, and adjust the deck pitch.

    But back to the subject. How many of you keep an eye on MAX Engine RPMs, and keep it there? Do you think MAX Engine RPMs are important, or not?

    I just have to know!

  2. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    I try not to go much over 10,000

    Seriously I have no idea what mine are but I've turned every one of them up as far as I can tweak it by ear,
    for the exact reasons you mentioned.
  3. Richard Martin

    Richard Martin LawnSite Fanatic
    Messages: 14,699

    The Kohler 25 I used to have would blow a head gasket everytime I would crank it up much over 3600 RPM. My current Kohler 28 EFI likes to drink fuel over 3600 RPM and it uses a tick of oil. Probably a pint in 50 hours. Since my old engine would start to use oil right before it blew the head gasket I'm a little leary of oil consumption. I generally set the RPM at around 3600 no load with the blades on. That's about 3650 with the blades off. If I need extra power I can just push the throttle all of the way and that turns it up to about 3700 no load with the blades on.

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