Results 1 to 4 of 4
  1. #1

    Join Date
    Jun 2013
    Posts
    7
    Location
    Ohio
    Mower
    YT4500

    YT4500 Yard Tractor Keeps throwing deck belt.

    I have a 2 year old (just out of warranty..) Craftsman YT4500. The 54" deck has started to throw the belt and will not keep it on for more than 30 seconds at a time.
    I route the belt properly, making sure the V-Belt rides the pulley's properly. It throws the belt so violently that it bends and twists a metal bracket that rides on the tension assembly.

    I also has this pulley replaced under warranty because it froze up. The replacement pulley needs replaced, the bearings are shot again, but it turns freely with no play.

    Here's the kicker....I think I know WHY it's throwing the belt, but not WHAT is causing it.

    I removed the two plastic covers to see the belt and spindle run. All is well, then about 10 seconds into the run (on the driveway, standing still not mowing) I notice the left most blade spindle belt appear to grow "thicker". I shut the blades off, but it throws the belt at the same time. I reset the belt yet again and run the same test. This time I catch it and stop it before the belt is thrown. The reason why it's thicker is because the belt has somehow TWISTED itself. What I was seeing was the V-belt completely around on the left spindle!

    I had my son monitor all the pulleys and we were able to catch it reversing on the clutch first, from there it appears to spread to the left spindle, and then fly off.

    WHAT could be causing this?? Any idea's? Now I did leave the twisted bracket off, not sure of it's function, but it was throwing the bracket (not as much perhaps) with it on. I have not been able to mow for 2 weeks now......

    I have damaged the belt, and bought a new one, but at $55 a pop, I don't want to ruin yet another belt.

    Thanks for any insight.

  2.  

  3. #2
    GentlemanFahmah's Avatar
    Join Date
    May 2010
    Posts
    51
    Location
    Sheldonville, Mass
    Mower
    Kubota

    Re: YT4500 Yard Tractor Keeps throwing deck belt.

    You stated that the idler pulley arm is bent, but attributed that to violence of the belt ejection. I suspect that your idler is misaligned and not fully retracting so it's allowing the belt to run too loose and then setting up the catastrophic failure. For openers, $55 for a belt is stiff, but its not as bad as it could be. If you are ruining belts when they eject, for sure you have pulley system alignment problems that need to be sorted out. Focus on getting the pulley and idler pulley pathways aligned and the idler pulleys springs and retractor mechanisms working properly. I'm betting that the first belt stretched and when it ejected, it misaligned the idler so it hangs and doesn't tension the v-belt properly. A little time on the web with the belt size and length will likely help you get that $55 cut down a good bit to a more affordable belt source. For $55, it should be kevlar and that should last a while.

  4. #3

    Join Date
    Jun 2013
    Posts
    7
    Location
    Ohio
    Mower
    YT4500

    Re: YT4500 Yard Tractor Keeps throwing deck belt.

    Quote Originally Posted by GentlemanFahmah View Post
    You stated that the idler pulley arm is bent, but attributed that to violence of the belt ejection. I suspect that your idler is misaligned and not fully retracting so it's allowing the belt to run too loose and then setting up the catastrophic failure. For openers, $55 for a belt is stiff, but its not as bad as it could be. If you are ruining belts when they eject, for sure you have pulley system alignment problems that need to be sorted out. Focus on getting the pulley and idler pulley pathways aligned and the idler pulleys springs and retractor mechanisms working properly. I'm betting that the first belt stretched and when it ejected, it misaligned the idler so it hangs and doesn't tension the v-belt properly. A little time on the web with the belt size and length will likely help you get that $55 cut down a good bit to a more affordable belt source. For $55, it should be kevlar and that should last a while.
    I do not believe the idler pulley arm is bent, the metal bracket I referred to is called the "keeper Belt Idler". (See item # 192 in the attachment) The main idler arm (#43) looks fine, but is a bit loose and does not hang level with the other pulleys. It's fully tight, but I'm not sure the reason why it has so much play.

    I've only just ruined the one belt, the original. It has some pretty deep gouges and nicks, but it is still in one piece. The mower is just over two years old and I have 54 hours on it.

    I think you're on to something, but not sure the best way to prove it out. Should I be able to place a straight edge across the pulleys and they be all level? I also notice that the belt always ride high on the Idler Pulley (#52) I thought this was because the magnetic clutch is so high up in the front. (it gets really bad in the lower deck level settings). Could my Deck adjustment settings affect this as well?

    When I first got the mower, I couldn't raise the deck to the highest level. (The deck has 6 settings) What I did was basically placed the lift mechanism in the highest position then hung the deck. I made the highest setting the mechanical high limit for the deck. As a result, the deck now bottoms out (hits the ground ) around setting 4. Before the deck operated between 2 and 4. (not sure why they made the perceived adjustment (1 to 6) less then the actual amount of travel available.) Could this way of adjusting affect the belt issue?
    Attached Images Attached Images

  5. #4

    Join Date
    Jun 2013
    Posts
    7
    Location
    Ohio
    Mower
    YT4500

    Re: YT4500 Yard Tractor Keeps throwing deck belt.

    Well, I tied to bend back what was bent and I also realize that the bearings in just about all the pulleys are bad. It looks good (better) and I have my new belt which really sticks to the pulleys mush more than the old one did. So I will make an attempt this weekend to use my mower and see what happens. I'm considering adding another washer to stiffen up the idler bracket, as even though I bent it (no easy task) it still has some up and down play fom wear the bolt goes thru it and it pivots.

Similar Threads

  1. Replies: 0
    Last Post: 06-10-2013, 01:00 PM
  2. Mower deck Belt keeps throwing on White brand mower HELP!
    By scion4xb in forum Mower & Equipment Operation
    Replies: 2
    Last Post: 05-16-2013, 07:12 PM
  3. Repairs throwing belt
    By Indian4dirt in forum Snapper Forum
    Replies: 19
    Last Post: 05-16-2013, 11:45 AM
  4. 400 series Yardman 400 series tractor keeps throwing rear drive belt
    By frank50e in forum Small Engine & Mower Repair
    Replies: 7
    Last Post: 05-08-2012, 09:34 AM
  5. Craftsman throwing belt?
    By Ron H in forum Small Engine & Mower Repair
    Replies: 0
    Last Post: 04-22-2011, 11:38 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •