You need to work out if it's fuel or spark. the eng maybe just flooded.
try holding the pedal to the floor and crank it over, it may take a bit to clear.
if it still wont fire, remove the air cleaner lid and while someone cranks it over try spraying carby cleaner or aerostart into the air intake (make sure you keep your face away from intake).
If it still wont fire you need to check for spark. remove number one wire and connect to an old spark plug with the gap opened up to about 4mm, you will need to ground the thread of the plug and then have someone crank it over, you should have a fat blue spark.