Riding mower just quit while cutting

Hey guys

This past weekend I was cutting the grass at my house with my John Deere GT242 and it just quit running. Made no kind of sounds or indications before hand that anything was wrong. Tried to restart it afterwards but it wouldnt. Engine will turn over but not start. Only other thing I can add here is the past few times I've cut I noticed that when I started it there was a puff of thick white smoke from the exhaust but after running a few seconds it would ho away. Any help would be appreciated.