Sounds like you flooded it. Hold the kill switch in, throttle wide open, and kick 15-20 times (this will serve to pump some of that excess fuel out of the cylinder). Put in a new plug and try to start it. You'll need to hold the throttle wide open when trying to start it too if its been flooded. You can check your spark plug by pulling it out of the head, reattaching it to its boot, and laying the end of it against the cylinder, then kicking the engine over. You're looking for a fat blue spark.