Why won't my craftsman 917259567 start?

Hello, i am having trouble starting my craftsman 917259567. I found that the ground wire came off the prong on the starter solenoid so i put it back on and it started. I tried again a day later and it wouldn’t turn over unless i touch the starter with 12v. I have replaced ignition switch, solenoid, battery, safety switch under the seat and brake/clutch switch. I just found that i have no power coming from the white wire that goes to the solenoid from the ignition. What else could cause this?