Mower deck belt jumping off again

[RalphVa]

Belt problems usually are caused by either pinch points on one of the pulleys or high points on the inner part of the pulley. These will cause thrown belts and/or will "eat" belts.

Look at your pulleys carefully all the way around inside.

Ralph

 

[Richard001]

Below is my marked up drawing of your JPG. I noticed that in your photo, the belt guide that would normally be installed on the tensioner pulley is not in place. I assume that you put that in after installing belt on the deck.



Do you have this item, number 9 in the photo below, attached to your engine?


The belt that is used on your mower is long. Power pulses from the engine and load variations from the mower blades can cause the belt to stretch and then relax. This will cause the belt tensioner to move around a lot. It only takes one loose moment for the belt to jump off one of the pulleys.

Richard

 

[jpilk99]

Belt problems usually are caused by either pinch points on one of the pulleys or high points on the inner part of the pulley. These will cause thrown belts and/or will "eat" belts.

Look at your pulleys carefully all the way around inside.

Ralph

Good thought. I checked (only with naked eye) and they look fine. Thank you though.

 

[jpilk99]

Below is my marked up drawing of your JPG. I noticed that in your photo, the belt guide that would normally be installed on the tensioner pulley is not in place. I assume that you put that in after installing belt on the deck.

View attachment 668338

Do you have this item, number 9 in the photo below, attached to your engine?
View attachment 668339

The belt that is used on your mower is long. Power pulses from the engine and load variations from the mower blades can cause the belt to stretch and then relax. This will cause the belt tensioner to move around a lot. It only takes one loose moment for the belt to jump off one of the pulleys.

Richard

Great notes/graphics overlayed on my JPG. Yes, I have part #9. Yes, I have my belt guide on the tensioner - just not in the picture. And Now I understand how to setup the additional guide with the rubber stopper - I'll get right on that. Thank you.

 

[jpilk99]

Below is my marked up drawing of your JPG. I noticed that in your photo, the belt guide that would normally be installed on the tensioner pulley is not in place. I assume that you put that in after installing belt on the deck.

View attachment 668338

Do you have this item, number 9 in the photo below, attached to your engine?
View attachment 668339

The belt that is used on your mower is long. Power pulses from the engine and load variations from the mower blades can cause the belt to stretch and then relax. This will cause the belt tensioner to move around a lot. It only takes one loose moment for the belt to jump off one of the pulleys.

Richard

Richard. I mowed yesterday with NO JUMPING. Not really sure why, but, I did take the tensioner arm off, clean everything, actually removed the old washer and put a rubber one in it's place (don't ask - I thought it would take the tiny bit of slop out of the arm) and then I did bend the arm up, with the pulley that you noted "moves with the belt", just a little so that it was ...reaching up toward the engine/drive pulley. I also did not lower the deck below 4.

I'm going to setup that rubber so that the tensioner arm can't ...over extend itself. Thanks so much!

 

[jpilk99]

Below is my marked up drawing of your JPG. I noticed that in your photo, the belt guide that would normally be installed on the tensioner pulley is not in place. I assume that you put that in after installing belt on the deck.

View attachment 668338

Do you have this item, number 9 in the photo below, attached to your engine?
View attachment 668339

The belt that is used on your mower is long. Power pulses from the engine and load variations from the mower blades can cause the belt to stretch and then relax. This will cause the belt tensioner to move around a lot. It only takes one loose moment for the belt to jump off one of the pulleys.

Richard

Richard. I mowed yesterday with NO JUMPING. Not really sure why, but, I did take the tensioner arm off, clean everything, actually removed the old washer and put a rubber one in it's place (don't ask - I thought it would take the tiny bit of slop out of the arm) and then I did bend the arm up, with the pulley that you noted "moves with the belt", just a little so that it was ...reaching up toward the engine/drive pulley. I also did not lower the deck below 4.

I'm going to setup that rubber so that the tensioner arm can't ...over extend itself. Thanks so much!

 

[jpilk99]

Re-posting here on this subject as my belt jumped the other day. When I stopped to inspect, I saw that the "tensioner arm restrictor post/arm/thang" was bent over pretty well, which - to me - means that that tensioner arm/pulley REALLY got yanked on. What's odd is that I was mowing on flat grass and didn't hit anything. Pretty confusing.

So I straightened out that "restrictor thang" (which I believe has been a godsend) and put another belt on, (the one that jumped was cut up a bit), and it seems to be running fine. But I held my iphone down while mowing to try and video the belt as it goes around. And while this short youtube clip of it ain't the greatest, and it's off kilter, it sure looks - to me - like that belt if ...floppin' around a fair amount and I'm hoping others can comment on if it appears to be acting normally or, indeed, it's kinda loose. Here's the link to the video and thanks in advance for any comments:

Jayt

 

[PuffyC]

Can't really comment on what you've done so far but I'll say that I had this exact problem before. Turned out to be a very small piece of twig that got wedged in the groove of one of the pulleys. Almost couldn't see it but I could feel it. My belt would jump around like that and everything would work for a while but eventually toss the belt. I'll add that in many hundreds of hours of extremely hard use I've never thrown a belt any other time so I wouldn't think a deck being slightly out of alignment would cause this but who knows. You may have done this already but I would triple check all those pulleys. Don't just look, feel each one all the way around. If you have one that's bent, or one with some small object wedged in there someplace, it would definitely cause what you're seeing.

 

[jpilk99]

I'll check the integrity of the pulleys. Thanks Puffy

 

[tomplum]

It seems as though it may be aggravated by the fact the deck in lowered. Where did it jump from? Remember as you scratch your head where the belt came off, think of the belt being pushed around the pulley system rather than being drawn around.