Max RPM for GXV160 Honda Powered Toro

Discussion in 'Mechanic and Repair' started by TXbulldog, Feb 23, 2007.

  1. TXbulldog

    TXbulldog LawnSite Member
    Posts: 28

    What is the factory recommended RPM spec for the GXV160 Honda engine on my Toro? The manual lists the max HP output at 3600, but the toro rep told me the mowers are usually set for 3250. I want to make sure the engine is set at the max recommended RPM so I don't bog down in heavy Bermuda grass in June.

  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    You answered your own question....;)

    If the max output is at 3600 that's where it can be set, That's where I set them.
  3. TXbulldog

    TXbulldog LawnSite Member
    Posts: 28

    I did some checking and found that the 3600 number is no load. Since this mower does not have a BBC do I have to remove the blade to test no load? Can the mower evern run like this? Or better yet, what is the max rpm with the blade engaged?

  4. Gbug

    Gbug LawnSite Member
    Posts: 57

    With my GCV160, I take it up to 3650, blades engaged. Doesn't seem to harm the engine and it cuts better.
  5. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    3600 with the blade on is just fine, 3650 as Gbug said is fine.
    As long as you stay close to the specified RPM you should have no problems.
  6. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Posts: 921

    The whole idea behind a max RPM on a mower is to not exceed a certain blade tip speed. I can't remember the exact FPS, (I think it's something like 17000 FPM), but it works out to around 3100 RPM for a 21" mower.
    I think that's a homeowner type standard whereas commercials can go a bit higher.
    Don't hold me to the exact numbers tho-
  7. TXbulldog

    TXbulldog LawnSite Member
    Posts: 28

    I believe the tip speed for a given distance from the center of the blade to a a specific location is calculated by multiplying the distance by the angular velocity. In simpler terms multiply the distance (inches) /12 x rpm x 2 x pi (3.14159). So...for a 21 inch blade spinning at 3250 rpms the tip speed is calculated as follows:
    Tip Speed: 10.5/12 x 3250 x 2 x 3.14159 = 17,870 ft/min

    If I increase my RPM to 3600, the new tip speed will be 19,792 ft/min.
  8. Mowingman

    Mowingman LawnSite Platinum Member
    from Texas
    Posts: 4,662

    Is that on a Toro commercial 21"? My experience with the Honda engines on those mowers has not been good. No matter what RPM you set it at, the engine is going to bog down in heavy grass. As a rule of thumb, those Honda engines are gutless dogs. No torque compared to the Kawasaki engine that you can get on those machines. If the mower is new, my suggestion is that you see if you can exchange it for one of the "good" Toros with the Kawasaki engine.

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