I have a murray riding lawn mower that keeps breaking the belt tensioner spring on the deck. I have inspected the pulleys themselves all OK. This unit is less than 2 years old. This will be the 4th spring I have replaced. Help trypod from Missouri

Hi,
This would be a guess. You have one or more sheaves(pulleys) that are nor symmetric in the area(s) that the belt rides in. This would show by the belt "dancing" or jumping a lot with the mower engaged. This would result in faster wear of the spring. Usually at one end or the other where it hooks. Usually caused by striking something with the blade(s) and opening up the "V" groove at some location.
Peace,
Clarke