I have a 1999 16hp Murry /Scott's lawn mower. It's an automatic with cruse control, Model # 42589x8. When I push the peddle forward it chatters bad, not so bad in reverse. Tractor does move froward and backwards, but slowly. Tractor came from a friend. My old tractor bought the farm last week. I need help in trouble shooting this problem. Jim

Hi,
Here is a link to the parts breakdown and refer to page17 to see the drive belt and idlers. My guess would be a seized idler. See:
http://www.outdoordistributors.com/pdf/Murray/MURRAY-MODEL-42589X8-LAWN-TRACTOR-(1999)-PARTS-LIST.pdf
Peace,
Clarke