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

[MParr]

A side comment on engaging the blades at low engine speed:
I had a 42" 16 (or 18?) hp 2009 Western Auto Wizard mower (I forget which of the 2 mower manufacturers of those days it was made by) - bought it used and used it for many, many years on a couple of rough acres.

Anyway - I was having to replace the very long blade drive belt 2 or 3 times a season. I would always engage the blade with engine running at relatively low speed and then speed it up to full speed to start mowing simply because I figure that's less stress on everything - it's just my habit of thinking that way in general.

I noticed that my wife always put the engine at full speed before engaging the blades. I got to thinking that that high-load shock was possibly killing the belt - the way the belts were failing (short sections were separating) supported the theory.

So I mansplained my theory to my wife (can be dangerous, but I took the risk ) and asked her to drop the engine speed before engaging the blades. She'd forget every once in a while, and I'd remind her (). Telling y'all all this to say that the belt started lasting well over 3 years between changes once we got the slow speed blade engagement thing established. Saved money and maintenance time.

The most important thing is to read the mower’s operation manual.
A PTO clutch operation is different than the old manual blade engagement of the older lawn tractors.

 

[RevB]

maybe a part damaged when lifting the mower for service? Like bent deck shell , etc. Look it over closely...

 

[RevB]

maybe a part damaged when lifting the mower for service? Like bent deck shell , etc. Look it over closely....

Ever try to bend 1/4 steel.

 

[RevB]

First time changing the blades and I wanted to make sure that if I had a failure with my install it would be at lower speed if that makes sense. Once I determined it was OK I cranked it up and mowed for about 5-7 min and then the blades just stopped working altogether in the middle of mowing.

What "stopped"? The entire drive system? Just the blades but the pulleys and belt kept going (damn near impossible)? Was the deck loaded up with rock hard grass? Were the blades the same length as old? Was the clutch still engaged when it "stopped"?

 

[RevB]

I tightened the belt a little yesterday but the squealing kept happening. It sounds like it's coming from the rear of the mower rather than above the deck. The manual indicates the spring tensioner should be .025 - .030 (or about the width of a credit card). I checked it and there wasn't enough space between the spring coils to get .025 minimum so I tightened and test drove again. Minimal change if any. The only thing I can think of at this point is either a new belt (less than 30hrs on this one) or tighten it again and see if it changes.

The bottom line is that I cannot for the life of me determine how the hell this happened in the first place. The blade replacement went perfect and I torqued it to manual spec with a torque wrench (110lbs). I lifted the mower with a MoJack lift by the front tires only. There is NO chance I damaged the unit during lift

Anyway. all of that to say, it's a fucken mystery folks! I would love to know what I actually could have done differently because I actually need to mow my two acres today!

Thank you to everyone who responded so far, it really helps the thinking process to get different perspectives, even the smartass one that suggested I buy a new mower. Haha

Have you manually spun the blades.....that means by hand.....with the mower off and check to see if anything is being struck by a blade? With your stump incident I wouldn't be surprised if a tear in the blade enclosure ( much less stout than the actual deck) is now being caught by a possible longer blade. Get under it and look, spin the blades.

 

[MParr]

Have you manually spun the blades.....that means by hand.....with the mower off and check to see if anything is being struck by a blade? With your stump incident I wouldn't be surprised if a tear in the blade enclosure ( much less stout than the actual deck) is now being caught by a possible longer blade. Get under it and look, spin the blades.

Read the previous replies.

 

[Peva]

The most important thing is to read the mower’s operation manual.
A PTO clutch operation is different than the old manual blade engagement of the older lawn tractors.

Good point about PTO vs. older manual type blade engagement. I believe PTO clutch has a little slippage while engaging.

 

[GrumpyCat]

The most important thing is to read the mower’s operation manual.
A PTO clutch operation is different than the old manual blade engagement of the older lawn tractors.

Country Clipper says:

Only engage the clutch with the throttle approximately 2/3 to full throttle and no load on the deck blades. Allow the blades to come up to speed and move the throttle lever to full throttle prior to cutting grass.

 

[RevB]

One of the nicest things you can do for your mower......

Why Does Your Zero-Turn Need a SoftStart Clutch Controller? | GDI

Having smooth clutch engagement every time you turn on your PTO is nice. Less of a teeth-rattling jolt when you engage your blades would certainly make any operator happy, but that isn’t why your commercial mower needs a SoftStart controller. Learn

www.gdimeters.com

 

[GrumpyCat]

One of the nicest things you can do for your mower......

Why Does Your Zero-Turn Need a SoftStart Clutch Controller? | GDI

Having smooth clutch engagement every time you turn on your PTO is nice. Less of a teeth-rattling jolt when you engage your blades would certainly make any operator happy, but that isn’t why your commercial mower needs a SoftStart controller. Learn

www.gdimeters.com

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?