keeps throwing deck belts

[Ed7oh]

I have a saber lawn tractor 1338 GS Model 13 horsepower Briggs and Stratton. it's starting to throw the deck belt, when the PTO arm is engaged I see the belt bouncing all Steins and the tensioner pulley bouncing up and down before it throwS the belt off. can the tensioner pulley be adjusted to tighten and stop bouncing and throwing the belt?

 

[Soundguy]

check all pullies for slop.. spindles included. also check spindles for drag.. a high drag can throw a belt.

check for off axis bends too. IE.. un-aligned pullies. belt may show wear on one side or another from this

 

[kco]

I had a Kubota that kept throwing the fan belt. After much frustration I spoke with someone who said the internal cords could be broken. The belt looked fine, but I replaced it and the problem was fixed. It is something to try after all other options.

 

[DFB]

I had an engine pully belt that kept coming off...new belt cured that

 

[yelbike]

Sounds like the tensioner, possibly needs a new spring. But also check the pulleys are all on the same plan, a long level works great. Hand spin each spindle and pulley looking for tight or wobble. Check for a bent deck also, cracked weld is a possibility also. Good luck.