Can you describe or post a pic of his cage? What are the temps and how are you controlling them? How old is he and how many times has he eaten for the previous owner?

Sometimes it takes a little while to get a new snake to settle in and eat. My advice would be to make sure his environment is perfect, leave him completely alone, and try to feed only once a week. When you do try to feed him, place a live rat pup or mouse fuzzy in his cage about an hour after sunset. Leave it alone in his cage with the lights out and leave the room.

Feed him whatever he was eating before (rats or mice), and don't handle him until he starts to eat for you.

Good luck!