Rotary Cutter Finish mower belt won’t stay on

[chinawall]

I have a 48” Taylor Way finish mower. Lately the belt keeps falling off. I’ve tightened the belt. The pulleys seem to be ok. I am wondering if the v of the belt has to be inward on the pulleys or is it something else? I would appreciate any advice

 

[oosik]

Your question about the belt on the pulleys suggests - check the routing of the belt again.

 

[RjCorazza]

Typically the spindles will be recessed to accept the V belt, and idler pulleys will be flat to accept the other side of the belt.
With the belt off, check each pulley for easy rotation with no wobble and that there is no debris jammed in the area where the belt rides. For idler pulley also ensure that it is not damaged. I have seen two part riveted together sheeves that were separating, causing belt problems.
I also agree that confirming correct belt routing is also a good idea, as well as the manufacturer specified tension.

 

[Beaver Cove Deere]

Make sure everything is inline and bolts are proper.

 

[zzvyb6]

I've had that problem. I found it to be caused by the vertical alignment of the idler pulley just before the belt heads to the transmission. Probably from heavy tugging on the belt while mowing very tall weeds. When the going gets rough, the extra pull makes the belt climb up and off the idler. New, straight bolt/idler axle took care of business.

 

[Williy]

The belt should not be protruding out side of the pulley

willy

 

[Captain Dirty]

... The pulleys seem to be ok...

Oosik's routing suggestion comes first as it is easy and cheap. In addition to the pulley checks described by RjCorazza also check the profile. The sheaves should have a straight sided "V" profile so the sloped sides of the trapezoidal cross section of the belt engage properly. After several hundred hours the belts on my JD F510 had worn the "V" into a "U" that allowed the belts to quickly roll and fall off or self-destruct.

 

[FPGT72]

I had an issue a bit like this, but it was a bearing in....I don't remember if it was a spindle or idle pully. Everything would turn just fine but if you went to mess with the (lets say pully) with the belt off you could feel the play. I am guessing when the deck was running that bearing would "wobble" a little bit, and that caused the belt to hop off. I know I replaced something, I want to say spindle as I know it was expensive, but don't remember if it was this deck or another one. It has been a day or two.

Bottom line, make sure there is no play in there, it might feel fine with the tension of the belt, but without you might feel the wobble.

 

[chinawall]

Really appreciate all the info!