Brand new mower deck belt keeps jumping off

[jpilk99]

Yep; it appears that the IDIOT factor was the problem. Still not sure how the physics of the mower deck changes because the blades were upside down, but, just thrilled that I can mow my massive lawn without the belt jumping everyone 90 seconds!

Thanks all!!!!!

 

[jpilk99]

Very strange, after putting on all new spindles, blades and belt ...that the belt continues to jump off. Especially when I have the deck quite low, 2nd lowest position to the bottom. I thought it might be my tensioner spring so I tightened that up. Seemed to help for a little while, but, ...

Could it be the arm that the idler pulley sits on is too loose, has too much play? (see video - IMG 2537 - YouTube ). I got a new pulley, but, the arm it sits on seems to have almost 1/4" of up 'n down play. I thought that was normal - to account for putting the deck either on it's lowest or highest position but now I'm not sure.

Thanks all,

Jay

 

[radios1]

Very strange, after putting on all new spindles, blades and belt ...that the belt continues to jump off. Especially when I have the deck quite low, 2nd lowest position to the bottom. I thought it might be my tensioner spring so I tightened that up. Seemed to help for a little while, but, ...

Could it be the arm that the idler pulley sits on is too loose, has too much play? (see video - IMG 2537 - YouTube ). I got a new pulley, but, the arm it sits on seems to have almost 1/4" of up 'n down play. I thought that was normal - to account for putting the deck either on it's lowest or highest position but now I'm not sure.

Thanks all,

Jay

it looks like #192 is missing, the belt guide, which keeps the belt in place when the idler loosens up.. I don't see that part on yours..

 

[jpilk99]

it looks like #192 is missing, the belt guide, which keeps the belt in place when the idler loosens up.. I don't see that part on yours..

Good catch . It's "on" but it's off to the side at the moment while i put the belt back on.

 

[jpilk99]

Good catch . It's "on" but it's off to the side at the moment while i put the belt back on.

Maybe this video helps, I'll try to take a better one, that shows the "tension" - which to me is still looking loose. IMG 2538 - YouTube

 

[radios1]

Good catch . It's "on" but it's off to the side at the moment while i put the belt back on.

is that the idler that the belt slips off?. if not, please post the exact pulley/idler that the belt slips off of.. check all pulleys/idlers for side to side play, if you get that, then bearings are worn, and could cause the belt to slip off!. that up and down play you checked is not the cause of your problem, but if you have side to side play, that could angle the belt, and throw it off the idler/pulley.. think of an I, if you had a belt on that, and angled it a bit to the left or right, the belt would slip off..

 

[jpilk99]

is that the idler that the belt slips off?. if not, please post the exact pulley/idler that the belt slips off of.. check all pulleys/idlers for side to side play, if you get that, then bearings are worn, and could cause the belt to slip off!. that up and down play you checked is not the cause of your problem, but if you have side to side play, that could angle the belt, and throw it off the idler/pulley.. think of an I, if you had a belt on that, and angled it a bit to the left or right, the belt would slip off..

Thanks. The idler pulley (#52) that is on the pivoting arm is brand new, and no side to side play. I'll confirm, but, I'm pretty sure the pulley right next to it, that is directly above the pivot arm - as well as the other idler pulleys - are all "tight", no side to side play.

 

[jpilk99]

is that the idler that the belt slips off?. if not, please post the exact pulley/idler that the belt slips off of.. check all pulleys/idlers for side to side play, if you get that, then bearings are worn, and could cause the belt to slip off!. that up and down play you checked is not the cause of your problem, but if you have side to side play, that could angle the belt, and throw it off the idler/pulley.. think of an I, if you had a belt on that, and angled it a bit to the left or right, the belt would slip off..

Wow. This thing is really kickin my butt. I've been wrestling the deck out from under and reconnecting the belt a couple times every mow. To your point earlier, there is no side to side play in any of the mower blade pulleys, nor in the idler arm pulley; all 4 are brand new and tight. The other 2 idler pulleys, if that's the correct term, one (#52 toward the right side of the deck as you look down at it and facing forward), has just ever the slightest bit of play - almost negligible. The other one, #39, that the tensioner arm pivots on/about, is snug.

Every time the belt jumps, it jumps off the DRIVE (#12 or #11) pulley.

For a couple of weeks, after putting on new spindles, blades, and deck belt, it was doing okay. But I could only mow at the 3rd lowest position. As luck has it, I prefer to have it in the 2nd lowest ...and every time I put it in there, it usually always jumps. Sometimes not, (maybe after running in the 3rd position a while), but, for the most part I can't use the 2nd lowest position any more.

Today is a disaster. Went about 50 ft in the 2nd position and it jumped. Got it back on and started in 3rd position, jumped immediately. Thought the tensioner arm had too much up and down play, so I took it apart and put about an 1/8" washer in there to snug it up, which it did, put it back together, belt jumped. Got another used belt that was in good shape, put it in, didn't get 2 feet and it jumped.

Help me. Please help me. . Thank you.

 

[tomplum]

Could you reference those numbers on a diagram please so we know that we are looking at the same thing.

 

[Carl_NH]

The idler pulley is usually tensioned with a spring and arm that when you tighten it the pulley actually moves to tighten the belt - is your idler pulley arm free? The belt tensioning pulley should move in an arc like 2-3" - if the swing arm is tight loosen the bolt with penetrating oil etc to get it to move back and forth.