My old mower is a 2014 Toro Zmaster 3000 series. I am pleased that I got 7 good seasons out of it.

As I mentioned here in probably October 2020, last season my old Toro had begun eating deck belts. I've been buying Stens 265-660 (that's also what the local yokels get you if you order from the local shop at the MSPR price of OEM but that's another story) for years. They've lasted a couple years until late last season where they now last about 3 weeks and sometimes only a couple days.

The belts and pulleys get extremely hot and the belt starts losing chunks and just snaps.

I've checked each pulley, they all spin freely, none of them wobble. I've replaced all the idlers. I've taken it back to the shop with the "Toro trained mechanics" and they found no issues.

I replaced the clutch myself but it worked fine for almost a year before this trouble happened. I've also run the clutch without a belt on and it doesn't heat up. I was thinking something got stuck in the clutch but it doesn’t seem to be the case.

I've got an OEM belt but I don't want to run it until I find the heat issue.

Any ideas what else to check?

I should also mention that the belts go on tighter than I ever remember. I did put the OEM belt on just now and it was all but impossible to get on. Could something have bent and caused the deck to shift forward causing the overly tight belts? I can’t find any issues.

I was going to say a bent pulley, pulley mount. If the belts are too tight they will heat up and fail

quote:

The belts and pulleys get extremely hot and the belt starts losing chunks and just snaps.

Is this (heat) an issue to look at?
If so can you reduce or isolate it?
What do you think is causing it?
If it is not transference from the engine then perhaps the belt/pulley is out of alignment and rubbing.

Given you've replaced the belts, and had similar issues, I suspect it's not a belt problem.

Not a mower tech, but I would guess maybe misalignment of one/both of the pulleys (i.e. maybe one/both shafts could be bent or may not be fully seated in their bearings? Or maybe the bearings are an issue?)

Not sure if measuring the alignment of two pulleys is straightforward - never had to do that myself. Hopefully it's a known process in mower-maintenance and if so, maybe that would be worthwhile diagnostic effort.

quote:

Originally posted by joel9507:
Given you've replaced the belts, and had similar issues, I suspect it's not a belt problem.

Not a mower tech, but I would guess maybe misalignment of one/both of the pulleys (i.e. maybe one/both shafts could be bent or may not be fully seated in their bearings? Or maybe the bearings are an issue?)

Not sure if measuring the alignment of two pulleys is straightforward - never had to do that myself. Hopefully it's a known process in mower-maintenance and if so, maybe that would be worthwhile diagnostic effort.

The super awesome Toro certified and trained mechanics claimed to have done just that. I have no reason to doubt them. I am assuming this is a non typical issue.

It is supposed to be my backup but it’s just too unreliable. I need to get this thing out of my garage.

Could it be that the belts are just old...even the ones you are getting for replacement and that is what is causing the issue. If you have gotten the “new” belts from one place, go to another place or order one online

You said the belts seem tight putting them on. Perhaps they're too tight after the clutch replacement. Try a larger belt.

quote:

Originally posted by mark123:
I have no reason to doubt them

Other than the burnt belts....

Check for a warped/twisted deck? I know you said the techs did this, but I would double check with a level. They may have checked the corners with a ruler or tape, but I'm not sure that would show all of the facts. Maybe pull the deck apart and check for high/low spots with a level? Check front to back, side to side, and both diagonals (X pattern) making sure to hit the centers of the spindle holes.

I'd also check the spring for the idler pulley. Maybe it is adjusted way too tight and pulling hard introducing heat into the mix.

Recheck all bearings to ensure rust free and lubed properly. If they have flat spots, it can cause heat.

Last thing I could think of is the PTO clutch. Does it have a brake that is stuck and getting hot causing things to heat up? I think some have a shim that can be removed.


Hope you get it solved. maybe hit the guys up on Lawnsite.com

One last thought...If you have a deck arm out of adjustment, the deck can be too far forward causing too much tension. Long shot, but still possible

Another long shot-egged out bolt holes or a loose (too long) hydro drive belt

If possible, get us a picture across the top of the deck with the belt on (a few different angles would be helpful).

Silly question, but since the belt is really tight. Is it routed correctly?

Owners Manual

Just in case there's something in there that might be helpful

When engaging the deck drive, does the motor pulley stretch the pulled side and slack the belt side going to the deck? I have seen enough slack for the belt to fall off the idlers and get chewed up in the process.

quote:

Originally posted by MikeinNC:
Could it be that the belts are just old...even the ones you are getting for replacement and that is what is causing the issue. If you have gotten the “new” belts from one place, go to another place or order one online

One or maybe even two but not six.

All my belts are getting more tight as I age as well.

It's rubbing on something if all the bearings have been replaced.

Is it possible the deck bent, and the pulleys are no longer square to one another?

quote:

Originally posted by r0gue:
Is it possible the deck bent, and the pulleys are no longer square to one another?

Absolutely. It had seven long and hard seasons. I do not baby my equipment.

quote:

Originally posted by Mars_Attacks:
It's rubbing on something if all the bearings have been replaced.

I suspect that’s correct but I just can’t find it. I wonder if an infrared camera would be useful in this case.

Mow some at night with the covers off. See if anything glows.