Riding mower deck belt keep coming off

[SAWYER]

I have a 42" deck and the belt keeps slipping off the pulleys. The belt doesnt really show wear except on the outer edges. I am not sure if that is enough to make it fly off, I did notice the right side of the deck is a little higher than the other side.

 

[boomerang]

Need more information. Model of mower and/or layout of belt. One belt driven off the engine that turns the blades? Or two belts, one which drives a master pulley on the deck that then drives a secondary belt for the blades, or what?

There are a number of ways this can be done. You need to be more specific.

But to get you started, make sure the pulley's are lined up. Assuming it's a one belt setup, the pulley's should be in the same plane. If they're not, something is wrong. A retaining bolt for the pulley has come loose or you have bad bearings. Also make sure the tensioning mechanism is still working. Any broken springs? Make sure all pulleys are still rotating smoothly. If one has bearings that have gone south the pulley could be cocked which will throw the belt. So, check the spindle bearings and check the tensioner pulley and the idler pulley if it has one. Check these with the belt removed. My guess is you will find one of them has eaten the bearings.

 

[SAWYER]

Itnis a White by MTD. The belt is the one that spins the blades, it goes on three pulleys

 

[mindless1]

Boomerang called it, but pull the deck off, which will make both finding and fixing it a lot easier, especially being able to crawl under it (jacked up and on jack stands) if the problem portion is mounted on the mower frame not the deck itself, and is a good opportunity to clean and lube everything too.

 

[skyking]

If either of the mandrels or idler has bad bearings, it will toss the belt.