You can flood it.

But chances are, you aren't priming quite enough. Try 2-3 turns of the prop after the fuel has reached the carb (with your finger still over the carb opening). Oh, and the throttle should be at full when priming.

Another way to do it is to cover the muffler exhaust with your finger and give is a shot with the starter. That forces a lot of pressure in to the tank and you get a lot of fuel quickly to the engine that way. Overdoing this will easily lead to flooding, but it can make it easier to start some engines.