Most gas engines have a diaphram fuel pump in the carb, so no pressure line is required. However, you will have to have vent line to your fuel tank to allow for air pressure equalization as the fuel is drawn from the tank.

Jeff

Not only is it not required, it would be down right dangerous. DO NOT PRESSURIZE your gasoline tank.

NorthropN9M, you are right, but what is the question? Rodney is right though, don't intentionally pressurize the tank.