I have a ryobi leaf blower model 280r and bought new gas lines but when I push the new lines on the plastic threads of the two pieces within the fuel tank and then push the white plastic washer up on the threads to trap the lines, the gas leaks from the tank. This is a unit that my father had and I'm trying to repair. Maybe I'm missing something in side the tank to seal the inside pieces with the out lines????? Can someone help me with this...looked easy to do.