If the engine is flooded, just hold the gas pedal to the floor and crank the engine until it starts... The extra fuel will eventually get sucked in or evaporate until it gets to an acceptable air/fuel mixture... Don't pump the gas pedal as that will make it worse... Holding it open will let the excess get out either with the engine cranking or evaporation through the carb...
Having to wait 10 - 20 minutes for the fuel to evaporate in a flooded engine is an old wives tale...