John Deere Riding Mower Won't Start?

I am using a snow blade on the front of my riding lawn mower. It will not start. I checked the battery with a multimeter. It's fine and registers 12 volts. I have 2 new spark plugs which I rechecked the gap and it looks good. There is plenty of gas. I apply the choke and immediately smell gas so I assume that gas is getting in OK.

By Marc