Also pressure check your tank. I like to pull both lines (or all three if you use a 3 line system, but I'll assume 2 line for now). Now pinch the carb line off and blow in to the vent and pinch it off while you are blowing. You've now pressurized the tank and are holding the air pressure in there. If you release the carb line, and have fuel or something in the tank, you should get a jet of fuel out. If the fuel doesn't squirt out then you have a pinched fuel line or a pressure leak or something obstructing fuel delivery to the engine.