22" push mower changed drive belt still has too much slack

Hi I have a craftsman self propelled push mower with 6.75 hp briggs and 22" cut. I recently replaced the drive belt because it was frayed in places and wasnt pulling. Now with the new belt it does the same still too much slack and the pulley barely moves when I engage the drive wheels. ANy ideas on adjusting this let me know...also it is the correct belt (same pn).

most likely cause is stretched cable, or warn out pulleys which i doubt, what you can do for an easy fix is get a belt that is slightly shorter (i know it is not the proper solution but it does work when you are in a pinch) always check your gear on the wheels as well.