If it is FLOODED (too much fuel) - Choke off, hold the throttle wide open, and crank the engine. If it catches, then back off the throttle immediately to avoid bouncing it off redline.

If it does not show any sign of firing at all after cranking for 5 or 6 seconds (no more) when doing this then either (A) you have fouled the spark plugs with raw fuel, in which case the only option is to replace them with new - and they will be quite obviously wet with fuel, or (B) the real problem is something else.