Mower Belt Keeps Jumping Off
Results 1 to 5 of 5
Like Tree3Likes
  • 2 Post By PikeCoGreenTractorMan
  • 1 Post By xcopterdoc

Thread: Mower Belt Keeps Jumping Off

  1. Top | #1

    Join Date
    Mar 2012
    Last Online
    07-31-2019 @ 04:09 PM
    Location
    Midwest
    Posts
    138
    Thanks
    9
    Thanked 6 Times in 5 Posts

    Mower Belt Keeps Jumping Off

    445 garden tractor, 54" mower deck, 1992-ish

    The mower belt keeps flying off when engaging the switch. Which would be better, engaging the mower at full throttle,
    or something less? I have been setting the throttle just under full throttle at perhaps 80-90 percent.
    And the belt usually flies off.

    I've replaced both idler pulleys. All the spindles seem to turn freely. Fluids is good, everything greased good.
    I've just ordered a new belt. So this is my last replacement item.

    If there is no improvement with a new belt, I'm going to have to check alignment of the pulleys,
    or something. This I don't know how to begin.

    Needless to say, this is very annoying, and tiresome.

    Thanks in advance.
    JD 4720, JD 445

  2. Remove Advertisements
    GreenTractorTalk.com
    Advertisements
     

  3. Top | #2
    PikeCoGreenTractorMan's Avatar
    Join Date
    Jul 2015
    Last Online
    Today @ 06:28 PM
    Location
    near Beaver, OH
    Posts
    414
    Thanks
    2
    Thanked 67 Times in 53 Posts
    Quote Originally Posted by stone7 View Post
    445 garden tractor, 54" mower deck, 1992-ish

    The mower belt keeps flying off when engaging the switch. Which would be better, engaging the mower at full throttle,
    or something less? I have been setting the throttle just under full throttle at perhaps 80-90 percent.
    And the belt usually flies off.

    I've replaced both idler pulleys. All the spindles seem to turn freely. Fluids is good, everything greased good.
    I've just ordered a new belt. So this is my last replacement item.

    If there is no improvement with a new belt, I'm going to have to check alignment of the pulleys,
    or something. This I don't know how to begin.

    Needless to say, this is very annoying, and tiresome.

    Thanks in advance.
    Stone7 - All items that I own that use a belt or PTO/gearbox to move blades get engaged/disengaged at idle, then throttled up to mowing RPM. Any belt has some "give" and flexes a bit while coming up to speed; induced slack over a spindle pulley may cause the belt to throw.

    I'd check your idler pulley springs, too, for integrity. We have one on one of our Simplicity that works itself to failure every couple of years, probably from the shock of on/off of the PTO switch. The spring induces tension on the belt. You might also have a metal bar or pin that helps hold the belt in place to prevent it from leaving the pulley.

    I hope this helps,

    Brian
    DRobinson and HydroHarold like this.
    Brian




    2005 JD4720 open station that replaced a thoroughly worn out late 1940's Ford 8N
    Factory rear wheel weights
    JD 400x loader
    1997 Farm King 7 ft RMFM
    KBOGH's; Pat's ECS for Cat-1 hitch
    5 ft. Bush Hog dating from the dawn of Mankind

    '94Honda 300 cc Fourtrax, '16 Honda 500 cc Foreman

    Misc. rusty implements
    2X Simplicity Riding Mowers
    Second-hand Homemade log splitter (aka " The Beast")

    46-1/4 acres in the majestic rolling hills in Southern Ohio

  4. Top | #3

    Join Date
    Mar 2012
    Last Online
    07-31-2019 @ 04:09 PM
    Location
    Midwest
    Posts
    138
    Thanks
    9
    Thanked 6 Times in 5 Posts
    OK, so, I've replaced both idler pulleys, the 2 plastic bushings, new belt and new spring.

    And presto!, the belt didn't fly off and I got some mowing done. It worked fine atleast this
    first time.

    I was really surprised how the new spring expanded, with the new belt. I could actually see
    daylight between the spring coils. Maybe my belt was way too worn out. I mowed until I
    choked the mower and stalled it out. I didn't have the heart try it again. I just stopped.

    I have 2 questions if anyone feels like commiserating.

    One, looking at everything on the deck, all the pulleys, except the spring tensioner, seem to be
    level, or flat to each other, or on the same plane. Is this the way it is? The way it should be?
    And the spring tensioner seems to have a bit of cant or tilt to it? Is this correct? The little bracket for this
    pulley was bent and I straightened it out. So if anyone can clear this up for me thanks.

    I'll ask my other question later.
    JD 4720, JD 445

  5. Remove Advertisements
    GreenTractorTalk.com
    Advertisements
     

  6. Top | #4
    xcopterdoc's Avatar
    Join Date
    Jan 2012
    Last Online
    Today @ 08:06 AM
    Location
    nc
    Posts
    1,629
    Thanks
    187
    Thanked 833 Times in 323 Posts
    They should all be on the same plane or within a reasonable tolerance. I would say 1/4 in.

    Sent from my LGL52VL using Tapatalk
    DRobinson likes this.

  7. Top | #5

    Join Date
    Mar 2012
    Last Online
    07-31-2019 @ 04:09 PM
    Location
    Midwest
    Posts
    138
    Thanks
    9
    Thanked 6 Times in 5 Posts
    Quote Originally Posted by xcopterdoc View Post
    They should all be on the same plane or within a reasonable tolerance. I would say 1/4 in.
    Thanks Copter,

    This kind of info, tech info, is hard to find even if it is written down anywhere.

    It seems to be staying on now. I air hosed off the top and didn't see anything underneath,
    and started it up and the belt stayed on.

    So there you go, change the belt when it starts flying off all the time.

    I mowed for about an hour until I encountered a tough briar right next to a tree in the yard.
    Going back and forth to get this guy, I bent the right edge in enough to hit the blade.
    This confusing racket was enough to cause a full stop landing.

    My mowing life is hell, enjoy.
    Although my ball peen was all it took to re-arise.

    It's not about the mowing, it's about the mower.
    JD, or someone, will probably steal that. We do not own our keystrokes, apparently.
    JD 4720, JD 445

  8. Remove Advertisements
    GreenTractorTalk.com
    Advertisements
     

Bookmarks

Posting Permissions

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