Joe,
Coming back to your original question. I always use 3 lines from my fuel tank. To carburator, to muffler pressuretap and a filler tube that stays plugged up all the time after fueling.
The pressure lineequalizes the atmospheric pressure and makes the fuel flow by gravity if the level of the fuel in the tank is higher than the carb. Which leads me to the conclusion that u have to lower the tank.