How To Perform Governor Adjustments on BBC Mowers

Discussion in 'Mechanic and Repair' started by OldLawnMowerMan81, Jul 3, 2012.

  1. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,337

    Thanx...I honestly didn't know what that meant....
    The first day I worked in a mower shop....they started me on commercial mowers...and never looked back.....
    Posted via Mobile Device
  2. OldLawnMowerMan81

    OldLawnMowerMan81 LawnSite Member
    Messages: 66

    The next time my dad tinkers with the engine, this time I hope it will read 3000 RPM on the TinyTach (this without the BBC engaged). When I then engage the BBC, it should read 2850-2900 RPM.

    To get a realistic idea of the actual blade tip speed of your mower with the BBC engaged, subtract at least 100 RPM from the manufacturer's stated no-load engine RPM.

    For example, if a Honda GXV140 engine on a BBC-equipped HR215SXA mower is turning 3100 RPM without load, then when you engage the Roto-Stop (Honda's terminology for BBC), the engine RPM should then amount to up to 3000 RPM.

  3. BigFish

    BigFish LawnSite Platinum Member
    Messages: 4,190

    You, in fact, want to adj. the top rpm's with the blade rotating it's the only way to get an accurate reading.
    The blades being engaged is not considered a load. It is a parasitic load, and should be accounted for when setting the top no load speed, which, by the way can be set to any rpm you want on your personal mower. I like to keep my unit at 3500 or so.

    Blade tip speed/ rpm charts based on blade length/ cutting dia. are online.
  4. OldLawnMowerMan81

    OldLawnMowerMan81 LawnSite Member
    Messages: 66

    Have you ever tried to determine the factory high speed setting by determining the overall tension of the spring?

    Also, what kind of loaded (blade turning) and no-load (blade not turning) speeds do you get on your Toro TNT100?


Share This Page