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Best RPM setting for my Super Z or any ZTR?

Discussion in 'Lawn Mowing' started by HenryB, Aug 6, 2006.

  1. HenryB

    HenryB LawnSite Bronze Member
    Posts: 1,828

    I've got my 24hp Honda set at 3500 rpm's my 27hp Kohler at 3550 w/out blades engaged. Both mowers 60 inchers. Any suggestions on the perfect rpm's?

    REALSLOW LawnSite Senior Member
    from FLORIDA
    Posts: 668

    My super Z dealer told me to run it wide open to keep the hydro's cooler but I do not like to do that 1 you get dirtier 2 the mower throws stuff hard , dangeruos!
  3. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    I don't know about the Honda but the Kohler can safely be run at 3600 RPM with the blades engaged.
  4. Scotts' Yard Care

    Scotts' Yard Care LawnSite Senior Member
    Posts: 343

    I think you might check your engine manual. Mine says to run the engine at full throttle whenever you're mowing as this ensures adequate cooling for the
    engine and probably for the hydros too especially if fan equipped.
  5. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    He is talking about governed engine speeds guys. Always run your mowers with the throttle lever all the way up when your blades are engaged.

    Both mowers should be set at no load 3600 rpms or up to 3650. Once the blades are engaged rpms will usually be about 100 lower.
  6. 6'7 330

    6'7 330 LawnSite Bronze Member
    Posts: 1,823

    None of the mower's I own incorporate a big Honda engine, only the small 5.5 HP engine.So I'm ignorant to where the rpm should be on a 24hp Honda.Both, Kawi and Kohler V-Twins are rated at 3800.The Kawi's on our last Exmarks were set to 3750, and Toro TurboForce Z-masters, 3830 right from the factory.We have set our Kohler's and Kawi's at 3800 since the introduction on the V-Twin engines.
  7. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    Same here... 3750-3800 RPM.

    No idea on the Honda.
  8. puppypaws

    puppypaws LawnSite Fanatic
    Posts: 8,915

    You are absolutely correct the air cooled engines should be run at their recommended rpm's at all times for the cooling system of the engine and hydraulics to perform to their optimal capabilities. That is why you keep the temperature lower on the engine and pumps by running the engine at full throttle.
  9. tacoma200

    tacoma200 LawnSite Fanatic
    Posts: 5,426

    I've heard this also but I've also heard that you should lower the rpm's after mowing for a few minutes to cool the engine down. As in put it to half throttle on the way to the trailer, load it and leave it running for a minute to cool off. Sounds like a contrdiction, but not sure which is right. I must admit I'm guilty of running my mowers at 2/3 throttle sometimes in tight areas or where I don't want to throw clippings as far. I think most of my yards are small enough that heat shouldn't be problem. I've also heard you should lower rpms in wet lush grass for clumping which has rarely ever been a problem for me exept on a Grasshopper.
  10. puppypaws

    puppypaws LawnSite Fanatic
    Posts: 8,915

    You let a diesel idle to cool down the tubo charger, I always let my tractors run for about 5 minutes before I switch them off but your air cooled engines and hydraulic pumps are cooling best when they are running their recommended rpm's. the fans are moving more air when turning faster. When you are even in a water cooled vehicle it cools better when the fan is turning good and you are moving air faster over the radiator, some vehicles in very hot weather when they are sitting at a stop light the temperature will rise but if you put your foot on the throttle and increase the engine speed it makes the fan turn faster, you can see the temperature drop a little. You should never run your mower at lower than recommended rpm's it is hard on the components, that is not to say you can't do it for a short time and not hurt anything such as a short distance you don't want to through the clippings very far but for cool down it will actually stay warmer at half throttle and cool more at full throttle.

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