My mtd slows down and then comes to a stop while going up hill. When shifted into 2nd or 3rd gear it will go.
Belt was replaced a year ago, problem has been getting worse sense belt replacement.

Can anybody explane how to adjust the belt or clutch . The unit is a 14.5hp 42" 7speed mtd yardman.

You really don't want to start messing with the adjustments very much. There may be the need for inspection / lubrication of pivoting points, and joints though.