Toro Super Recycler 20384 Belt Pulley

[OldToroGuy]

I have a 2020 Toro Super Recycler, Electric Start and the drive belt slipped off the engine pulley for some reason. The last time I used it was on some on-even ground, grass wasn’t very tall but the traction was fine as I remember. My wife used it the other day and complained she had to do a lot of pushing. I tried it and sure enough the drive wheels weren't working at all. I first tried adjusting the drive cable without any luck. The mower has had very little use since I bought it and probably set for 2 ½ - 3 weeks since that last time I used it.

I finally tipped the mower over and took off the blade and could see the drive belt had slipped off the top of crankshaft pulley, called the "Driver, Blade", Part Number 106-3987, on these newer Toro models. This "Driver, Blade" is different than the older Toros because it slides right off the crankshaft after removing the blade bolt. This "Driver, Blade" has a fixed key inside its shaft hole. The fixed key will only fit into a long keyway slot on one side of the crank. There are also two small individual keyway depressions on the opposite side of the crank probably for a different model. I've reassembled everything and the mower seems to be just fine now. It's still a mystery to me why the belt slipped over the top of the pulley. There is a gap about the width of the belt between the top of the pulley and the bottom of the engine.

Has anybody had a problem with the drive belt slipping off the drive pulley/Driver Blade on their Toro? It never happened to my old Toro Super Recycler. Should this Driver Blade slide easily on and off the crank? Thanks in advance.

 

[StarTech]

I don't see the belt retainer for the belt at the engine pulley.

 

[OldToroGuy]

No, I didn't take a picture of the belt guide but it was there along with the grass shield

 

[Rivets]

I’ve seen this many times and the main cause is a piece of mulch or small branch gets between the belt and pulley forcing the belt off the pulley. Problem is most times the user just keeps pushing the mower and burns the belt, which means after they put the belt back on it will jump off again a short time later. I always recommend replacing the belt ASAP when this occurs. Yes, the blade adapter should slide on and off easily if properly maintained.

 

[OldToroGuy]

That blade driver is quite rugged looking but the key in it looks kind of delicate. I don't know why you would need to replace them unless you were prone to hitting a lot of immovable objects like rock, stumps, or boundary markers. They must need to be replaced a lot because when I Googled them up there are a ton of them out there from $11+ to $25 or so. Rivet, should I pick one up, just in case I ever need one in a hurry?

I'll double check my belt but it looked to still be in good shape and it hadn't been that way long obviously. I didn't smell any burning rubber or anything like that and didn't see much damage to it. I don't ever remember that happening to my old Super Recycler. Both of my Super Recyclers I bought from a Toro Dealer, I thought they were both worth the money.

 

[Rivets]

In the past 25 years I’ve probably replaced about a dozen of those blade adapters and I’ve been working for Toro dealerships. Most times it is because the owner didn’t do any service on the unit and the adapter froze to the shaft. Maybe two or three were the broken key when they hit something hard. You will have to make a choice as to whether you want an extra one on hand. Personally I don’t see a need. I think you would be better off having a spare belt on hand.