I have a snapper rear motor 12.5 horse it will" not" take of in the low forward . But I can put it in high gear it will take about 30 sec before it takes of. Reverse is fine. What do I have to do to fix this ? This is a 79 model ,

There is a tension spring that holds the drive disc tight to the variator pulley. It may be missing or the variator pulley bearings are bad. Variator (dinner plate) Drive wheel (disc with rubber band)

Don