I need help!! starter/Ground issues!

Here’s how it goes, riding about this time last year in Francis Marlon Nat forest, and we were riding for about 4 hours and then my rancher cut off! Wouldn’t start back. No lag in engine or anything. Just would not cut on. So pulled to truck n loaded. Brought home and tried sum things, no help. Will not get any fire. Changed solenoid and then starter, still no luck. The positive wire was very hot for the longest, so hot that it would feed bk to the battery and melt through the post! Has anyone had this problem?? HELP.