Belts slinging off Toro

Discussion in 'Lawn Mowing' started by ACE, Oct 19, 2000.

  1. ACE

    ACE LawnSite Member
    Messages: 36

    Please help anyone? I have a Toro 620Z and recently the deck started to shake a lot. Local dealer said my 20hp Onan had a harmonic imbalance. I have replaced all belts but still have so much vibration on the belts that the blade belt keeps coming off.
  2. curlawngreen

    curlawngreen Banned
    Messages: 309

    Check spindels and pulleys and idlers.
  3. lbmd1

    lbmd1 LawnSite Senior Member
    Messages: 462

    What model Toro Z is it and what year? If it's a 1998, then there is a pulley retrofit from Toro to keep the mule belt from constantly falling off. Ours was falling off all the time. Also check under the top deck plates where the grass accumulates. This can also cause the belts to work harder and jump off.

  4. chrisbolte

    chrisbolte LawnSite Member
    Messages: 135

    My belts got real hot once and belts strecthed and kept falling off and needed to be replaced
  5. LawnSite Member
    Messages: 57

    check inside of pulley v groove real carefully for anything that might be wedged inside like pebble wood ect... causing it to jump. another way to check is to turn belt by hand and see if belt has any high spots when doing this. that would be indicator of something underneath. maybe belt tesion?
  6. ACE

    ACE LawnSite Member
    Messages: 36

    Thanks for all the comments. Toro suggested that I check the pullys and tension on the pullies. I'm not sure about that becase they seem to have a fair amount. I may have wore spots on the pullies from locking the blades up in tall grass.
  7. Vandora Lawn & Landscape

    Vandora Lawn & Landscape LawnSite Senior Member
    Messages: 386

    Loosen the idler pulley till its got flop when you engage it (WITH THE MOWER OFF!). Then tighten it till you get no more flop. I just did it on mine. My belt kept flying off when I let the blades spin down. Also, let the blades of easy by easing the lever back.

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