Yard Machine Riding Mower Won't Start?

I have a Yard Machine riding mower. It won't turn over by the switch, but I can jump start it at the starter with my jumper battery box. It started doing this about 3 weeks ago. I turned it off and when I went back to start it it would not turn on by the switch. After about the 8th time trying the switch it started, but hasn't since.The pto is on the right and you have to pull it all the way back. The fuse under the seat is good. Thanks for any help.

By David