I have had this problem once with a yamaha, there is a inline fuel filter or water seperator on your motor somewere, also on the end of your fuel pump there is a tiny filter screen on the end of that pump you probably have some trash on in that screen causing it to choke the amount of fuel that can go in the motor. clean that you will haft to remove the pump from the fuel pump housing, and then add a high volume filter at your tank.