Kind of late to the party, but the fuel pump won't pump if the check valve in the pump doesn't work. I would guess this isn't the problem as it worked before, but if the pulse line from the bottom of the motor is leaking, it won't supply fuel, and if the inlet from the tank has any air leaks, it won't draw gas.
You need to find out if the gas is getting to the fuel pump, and then if it is getting to the carbs. sounds like it might be a fuel pump issue or a needle and seat issue. Easy to get the lines mixed up on the fuel pump.