54" BAD BOY MZ Magnum (zero turn) Blade Replacement OEM Blades - Blades Slipping

[RevB]

My dealer has an assortment of belts hanging on the wall which were shredded by owners starting the blades at idle. As an example of, “don’t do this.”

I don’t understand how this “soft start” would not create more problems than it solves?

That's the problem with not understanding physics.....it acts over milliseconds not instantaneously. The difference between letting the clutch out slowly or just dumping it. But I guess if all you've ever experienced is an automatic that makes no sense either.

 

[GrumpyCat]

That's the problem with not understanding physics.....it acts over milliseconds not instantaneously. The difference between letting the clutch out slowly or just dumping it. But I guess if all you've ever experienced is an automatic that makes no sense either.

Mechanical engineer driving manual transmission since 1975. Try me on the physics.

Fact: Idle speed activation of electric PTO shreds belts. Manufacturer says 2/3rd to full throttle when activating.

What the manufacturer says is not intuitive but real world experience supports their instruction. Yet you claim an aftermarket gadget makes it better? How? “Milliseconds” suggests slipping the expensive clutch rather than slightly less expensive belt. The manufacturer doesn’t seem to think this is necessary. Perhaps the blade drive is designed to absorb the shock of dumping the clutch? Motorcycles are designed to withstand dumping the clutch.

 

[BigBlueEdge]

If the blades are the issue you could check by putting the old ones back on temporarily and seeing if the belt issue goes away. While off, you can weigh the blades to see if there is a significant difference.

This is a stretch, but could you have put the blades on backwards? Maybe turning the blades the wrong way causes more drag (blades have lift wings, no?) and that is straining the deck drive system. Wild ass idea, but I've heard weirder things happening.

 

[ddbtdd]

First blade replacement. Went very smooth. Maybe too smooth.
Completed the installation, took the mower out for a test-drive, it was working great. About 5min the blades stopped turning.
Disengaged the blades with the cutoff switch, took it back into the garage, lifted it and checked the torque on blade bolts to ensure 110 ft lbs.
Torque was good.

• Started mower
• Engaged the blades (low speed)
• Belt squeal and smell
• Tightened front tension spring
• Started & engaged the blades (low speed) no squeal
• Test drove - engaged blades at full speed, squealing.
• Gave up on it before I took a hammer to it.

What could cause the belt to loosen when I never touched it while replacing the blades and the last time I ran the mower (before the blade change) it was fine?

What step did I miss when changing the blades that might cause the belt to loosen?

BTW - I never even touched the belt at all. All the work was performed under the deck the entire time.

 

[ddbtdd]

First blade replacement. Went very smooth. Maybe too smooth.
Completed the installation, took the mower out for a test-drive, it was working great. About 5min the blades stopped turning.
Disengaged the blades with the cutoff switch, took it back into the garage, lifted it and checked the torque on blade bolts to ensure 110 ft lbs.
Torque was good.

• Started mower
• Engaged the blades (low speed)
• Belt squeal and smell
• Tightened front tension spring
• Started & engaged the blades (low speed) no squeal
• Test drove - engaged blades at full speed, squealing.
• Gave up on it before I took a hammer to it.

What could cause the belt to loosen when I never touched it while replacing the blades and the last time I ran the mower (before the blade change) it was fine?

What step did I miss when changing the blades that might cause the belt to loosen?

BTW - I never even touched the belt at all. All the work was performed under the deck the entire time.

 

[ddbtdd]

Something has obviously disengaged. Check the routing of your belt.

 

[Freddie21]

Kinda reaching here, but remove the belt pulleys and blades off the spindle shafts. Clean and inspect the splines on both ends of the shafts and the mating pulleys and belts Check all idlers for correct alignment to others and spins freely and quietly. Check belt tension at all deck heights. Check blade levelness by rotating blades till tips touch and compare their heights.

 

[JHPArizona]

With the pto disengaged, the blades should freely turn by hand. If not, take belt off, and check each blade spins freely.

 

[RandyT]

No chance. I lifted it using a specific jack meant to lift the unit and used only the front tires as a point of contact. I also used a 500lb impact to remove the bolts to ensure the blades didn't spin and then torqued the new blades to 110 ft lbs with a torque wrench after install. This is what is puzzling me so much. There was no incident at all with the remove and replace of the blades and the mower functioned perfectly all the way up to the last cut other than the blades being dull and needing replacement.

Crazy!

Do some basics. Take the belt off compare length to a new one. Some lesser brands will stretch. If that is not the case check the gap on the electric clutch with a gauge. Only 30 hours the seller should do it under warranty. After hitting a stump look at all pulleys closely by lifting sides up and down for play. Seen many things happen over the years, start withe simple and weakest points of the drive system and work forward.

 

[Gord Baker]

First blade replacement. Went very smooth. Maybe too smooth.
Completed the installation, took the mower out for a test-drive, it was working great. About 5min the blades stopped turning.
Disengaged the blades with the cutoff switch, took it back into the garage, lifted it and checked the torque on blade bolts to ensure 110 ft lbs.
Torque was good.

• Started mower
• Engaged the blades (low speed)
• Belt squeal and smell
• Tightened front tension spring
• Started & engaged the blades (low speed) no squeal
• Test drove - engaged blades at full speed, squealing.
• Gave up on it before I took a hammer to it.

What could cause the belt to loosen when I never touched it while replacing the blades and the last time I ran the mower (before the blade change) it was fine?

What step did I miss when changing the blades that might cause the belt to loosen?

BTW - I never even touched the belt at all. All the work was performed under the deck the entire time.

It is likely that you have 1 or More Spindle bearings seizing up.