Mule drive belt popped off inside pulley?

[Pullstart 67,042]

I’ve never had this happen.  Thoughts?  Too tight?  Too loose?  Worn belt?  

 

14 Automatic, electric clutch.

42” RD deck.

Sharp blades, greased spindles, quiet and tight bearings.

[peter lena 9,309]

@Pullstart  sounds like a combination of related rotational issues , ENHANCED  BY ELECTRIC  CLUTCH , sudden severity  of  rotational drag areas , ever service those 6203 , bearings in the mule drive ?  that belt wear is showing you the way , BTW those bearings have wide rubber  side grease shields , what could you possibly do ? that would be my first , look see . that instant violent engagement , demands related smooth / easy movement . lubrication failure  is probably  right there , just my view , pete

[Ed Kennell 42,171]

Looks like that belt needs a haircut.   I see rust in the Vee pulley that may be wearing the belt.   Clean all the pulleys and get a new belt.   

[JoeM 8,429]

Just thinking out loud. 

Drive side of the belt pops off.....has to be too loose. (but how did it force it's way out of there?) 

Is there something in the deck rigging not right causing misalignment and looseness? 

A worn belt will slip but generally will stay on the pulleys. 

Mule drive bearing starting to fail.

 

that is a weird one Kev. 

[peter lena 9,309]

@JoeM  often refer to , pto  drive belt , to mule drive movement ease , by hand . I regularly hear  my neighbors screaming  deck engagement , not a clue ,  or care ,  pete  

[Pullstart 67,042]

I did my best to make sure this was set up well.  This mule/belt/deck has not been on this machine before, but that shouldn’t matter much.  I’ll clean the pulleys and see about a nice belt.  

[ri702bill 9,534]

3 hours ago, peter lena said:

ENHANCED  BY ELECTRIC  CLUTCH , sudden severity  of  rotational drag

Pete pegged it. E-lectric clutches are the all-or-nothing style. There is no way to  ease into getting the belt moving short of being just above idle speed. Not my favorite.....

[Pullstart 67,042]

14 minutes ago, ri702bill said:

Pete pegged it. E-lectric clutches are the all-or-nothing style. There is no way to  ease into getting the belt moving short of being just above idle speed. Not my favorite.....

Funny, this was during operation.  It was working, then it wasn’t.

[midpack 1,011]

26 minutes ago, ri702bill said:

Pete pegged it. E-lectric clutches are the all-or-nothing style. There is no way to  ease into getting the belt moving short of being just above idle speed. Not my favorite.....

I have a "soft start" module on my electric PTO,  this allows for a much smoother engagement. My snowblower used to really jump when the PTO was activated. Now it's about the same as my manual PTO machines 

That's pretty tall grass for a RD deck, might have something to do with the belt coming off 

Edited July 2 by midpack

[cafoose 3,456]

41 minutes ago, midpack said:

I have a "soft start" module on my electric PTO,  this allows for a much smoother engagement. My snowblower used to really jump when the PTO was activated. Now it's about the same as my manual PTO machines 

That's pretty tall grass for a RD deck, might have something to do with the belt coming off 

Good to know @midpack

 

 

[midpack 1,011]

I must be getting old, forgot about that post. 😅

 

And 3 years already. It's done some serious snow removal with no problems/complaints yet

Edited July 2 by midpack

[squonk 43,939]

Another thing. Look at what you're mowing. That's not Lee Trevino's practice green there and that's not a gear drive brush hog. You may have hit something that briefly stopped the blades and the belt popped off as the weakest link in the chain. Or one of those stalks could have entered the mule's chat room and popped the belt off. That belt side is moving forward as it was turning and a sudden stop would push a loose worn belt right off. 

 

Edited July 2 by squonk

[Pullstart 67,042]

That’s about 2 weeks of growth right now 

[953 nut 60,349]

I have had a piece of debris (small twig or a clump of sod) get under the belt and derail it. Could be the idler or the deck drive pulley picked up something.

[8ntruck 7,877]

I found a piece of a stick jammed in one of the pulleys once when I was chasing a belt twisting inside out problem.

[Lee1977 7,224]

These old decks have worn lift part and It usually take more then the first tighten for them to get adjusted even in regular lawn grass. That belt is trashed, I've had better looking belts to turn up side down, 

My old 48" deck sounds like a trashing machine, but there is nothing wrong with the belts, pulleys or bearing. After installing it I have had to tighten the belt twice on it in the yard before it got an adjustment it liked.

 A tight lightly used deck you can get adjusted the first time.

Edited July 3 by Lee1977

[kpinnc 14,712]

10 hours ago, midpack said:

I have a "soft start" module on my electric PTO,  this allows for a much smoother engagement.

 

I have one, and it's worked great on my zero turn for several years. I will definitely use one on EVERY electric clutch that I use in the future. 

[JoeM 8,429]

I engage my xi clutches at half throttle. Not a soft start but not nearly as violent 

Not much for those soft start electronics, wears the facing out with more slip on the clutch with larger decks. 

[pfrederi 18,714]

5 hours ago, JoeM said:

I engage my xi clutches at half throttle. Not a soft start but not nearly as violent 

Not much for those soft start electronics, wears the facing out with more slip on the clutch with larger decks. 

Since both "facings" in an Electric PTO are steel.....not sure wear is a huge issue...

Edited July 3 by pfrederi

[JoeM 8,429]

2 minutes ago, pfrederi said:

Since both "facings" in an Electric PTO are steel.....not sure wear is a huge issue..

Out of the dozen machines. I had a couple clutches that would slip so bad the deck would not spin up. Of course they are used and they were grooved down to the rivets. Hard to tell how many cycles and under what circumstance. One had less than 1K hours. 

Something i do to used clutches is to de-glaze them with a 60 grit flap disc. The metal to metal facings get super smooth and shiny. Removing the shine with a little cross hatch. 

I might have kept one for the coil, if I think about it I'll get a pic and share. 

Also, some of the newer clutches are adjustable, the ones on the xi machines I have are not. 

[kpinnc 14,712]

8 hours ago, JoeM said:

I engage my xi clutches at half throttle. Not a soft start but not nearly as violent 

Not much for those soft start electronics, wears the facing out with more slip on the clutch with larger decks. 

 

I'm not sure what the number of engagements or duration of use becomes "normal", but 5 years of mowing 3.5 acres year round haven't worn my clutch with a 61 inch deck. 

 

I can also verify that not once have I damaged a belt since installing the controller. 

 

The controller uses a single wire to sense the RPM of the engine thru the pulses generated by the spark plug wire. The force of the engagement is based on the speed of the engine, and the clutch still fully engages in less than one second. 

 

If slower engagements of the clutch was a factor in the speed of wearing the clutch face, the number of hours combined with the number of engagements would likely have destroyed my clutch by now. Not once have I even had to adjust the clutch  tension in the years I've used it. Even now my clutch doesn't slip once engaged. 

 

I am not openly disputing you, because your opinion is plausible. I'm just letting you know that it doesn't work the way it seems that it would. The product for me at least actually is the opposite. There are plenty of testimonials out there that show the same results I have experienced. 

 

So many products are snake oils and flakes at best. This is one item that not only works as advertised, it extends the life of the overall system. 

Edited July 3 by kpinnc

[JoeM 8,429]

2 hours ago, kpinnc said:

This is one item that not only works as advertised, it extends the life of the overall system.

I believe you and would say you are one that is easy on his machine. 

 

My thought is to soften the start you have to have slippage or reduce the input HP. 

 

I just reduce the rpm to half or a third and it is pretty smooth.

 

I have a neighbor that mows about 1 1/2 and she must restart her blades 10 plus times when mowing, either forgetting to activate the back up feature or to stop and check her phone! 

 

 

[kpinnc 14,712]

2 hours ago, JoeM said:

My thought is to soften the start you have to have slippage or reduce the input HP. 

 

If you think about a manual Wheel Horse PTO, they typically get engaged fairly slow. Many of those clutch pads have lasted decades. Of course proper adjustment is critical. 

 

With the clutch controller, the clutch is engaged with a short series of very fast pulses- much like antilock brakes. All in less than a second before solid engagement. Make no mistake it is still abrupt, but it isn't like a gunshot. 

 

2 hours ago, JoeM said:

I have a neighbor that mows about 1 1/2 and she must restart her blades 10 plus times when mowing, either forgetting to activate the back up feature or to stop and check her phone! 

 

I restart my PTO several times (to dismount if I need to move or pick something up) but my Scag has no reverse shutoff. Not even sure how that would work on a zero turn. Both drive wheels run in opposite directions almost as much as they run the same direction. 

 

 

 

[lynnmor 7,858]

On 7/2/2025 at 7:53 AM, Pullstart said:

I’ve never had this happen.  Thoughts?  Too tight?  Too loose?  Worn belt?  

 

14 Automatic, electric clutch.

42” RD deck.

Sharp blades, greased spindles, quiet and tight bearings.

I wonder about that downward tilt on the mule, perhaps wrong belt or pulleys?

[peter lena 9,309]

@midpack  that soft start module , sounds like it might help a lot of people , have any  related info on it ?  pete