iI HAD A PROBLEM WITH AIR BEING SUCKED INTO MY FUEL LINE THOUGH THE OTER MOTOR.MY REMEDY WAS I RAN ONE LINE FROM MY MAIN FUEL TANK TO MY WATER SEPERATOR,I THEN ADDED TWO SEPERATE (OPEN -CLOSED) VALVES, ONE TO TROLLING MOTOR AND ONE TO MAIN MOTOR.I KEEP THE MOTOR THATS NOT BEING USED CLOSED. GOOD LUCK