I have a Murray mod. 425001x8b riding lawnmower. I checked to make sure belt was attached to pulley. Does anyone know were tension spring is located and how to adjust this. I This might be the problem. Thanks Steve

Hi,
It would be item #21 on page 8 of the breakdown at the end of this link:
http://www.outdoordistributors.com/pdf/Murray/MURRAY-MODEL-425001X8B-LAWN-TRACTOR-(2004)-PARTS-LIST.pdf
Peace,
Clarke