Help with belt popping off on 48" Bobcat

Discussion in 'Mechanic and Repair' started by MrNetvestor, Jun 20, 2013.

  1. MrNetvestor

    MrNetvestor LawnSite Member
    Messages: 13

    Hi all:

    I have a 48" Ransomes Bobcat walk behind and the "PTO" belt comes off the blade idler pulley and then shreds to pieces.

    I've attached 3 pics to show what I believe is the issue.

    1st pic shows pulley and belt layout.

    2nd pic shows what happens to the belt after disengaging the blades. When I reengage the belt gets caught under the blade idler pulley and it's toast.

    3rd pic shows how the belt lays from the engine shaft PTO pulley to the blade idler pulley. The PTO pulley on the engine shaft seems to be quite a bit lower. The only possible adjustment I can see is what might be a spacer above the PTO pulley...between it and the pulley for the trans/wheels.

    Does anyone have any idea how to remedy?


    Bobcat 1.jpg

    Bobcat 2.jpg

    Bobcat 3.jpg
    Last edited: Jun 20, 2013
  2. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Messages: 452

    Belt guide on idler doing nothing, nrrds to be on other side stopping belt from coming off.
  3. MrNetvestor

    MrNetvestor LawnSite Member
    Messages: 13

    I thought the same. However, the guide seems to be pressed in or welded.

    Am I wrong? I'll go take another look as well....
  4. MrNetvestor

    MrNetvestor LawnSite Member
    Messages: 13

    OK, went out to the mower and after a bit of pulling the guide came off. It almost looks as if the guide was stuck to the bracket by the paint on each component being stuck together.

    In any case, I reversed the guide and have fingers crossed that it keeps the belt in check.

    Thanks for the keen observation.

    On a side note: Does the level mismatch between the PTO (on the engine shaft) and the blade idler pulley appear to be normal?
  5. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Messages: 452

    Looks like possibly your trans pulley is also not slid all the way up to the bevel in your crankshaft. Look how the edge of the trans belt is starting to fray. I thought there was a spacer between blade belt pulley and retaining washer on crank. I will look in my paper manual tomm. and see what the correct setup is suppose to be.

    How close to the idler did you get the belt guide?? I've seen a ton of these set-ups that after time the green idler bracket goes over center and then blade is hard to dis-engage, or will bend rod. I will drill a hole in side plate and install a fully threaded bolt with 2 nuts, one on each side of bracket, as a stop for the green idler pulley bracket.
  6. goel

    goel LawnSite Member
    Messages: 73

    When's the last time you replaced the spring?
    Posted via Mobile Device
  7. monoshock

    monoshock LawnSite Bronze Member
    Messages: 1,323

    Yep, I have the same mower. Also looks like the belt is to loose.
  8. monoshock

    monoshock LawnSite Bronze Member
    Messages: 1,323

    Another thing I did on my Ransomes/Bodcat, is to use a 2" hole saw and drill holes in the deck cover to help speed up changing the blades.
  9. herler

    herler LawnSite Fanatic
    Messages: 5,139

    The belt guide in and of itself isn't designed to keep it from happening during operation, the belt guide is only there to keep the belt in place after it is disengaged and there's no tension on it, once that belt is engaged however the belt should stay in place guide or not.

    One of the more common problems for belts popping off is the bearing in the idler pulley has went or is going bad, the good news is that testing it is a simple matter of grabbing the pulley and checking for wobble, the bad news is that if the bearing is bad the only solution is to replace the whole pulley.
  10. MrNetvestor

    MrNetvestor LawnSite Member
    Messages: 13

    Thanks for all the advice!

    I believe relocating the guide will solve my problem.
    The belt would break after being disengaged, falling under the idler pulley and then reengaged. Now the guide will prevent it from going under the pulley.

    I checked the pulley and the bearing seems to be tight with near zero play.

    Not sure if the belt is loose as it's in the disengaged position in the pic. Is there a way to tighten it? I'm not seeing how this would be done.

    Thanks again. I'll post shortly with a question about the small oil leak at the base of the 14hp Kawasaki engine next.

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