I am experiencing loss of power in the hills and take off it feels like a fuel problem. I have changed fuel filters several times and checked all the fuel lines. I blew air thru them and all was fine. The only thing I noticed is the return line is dry - does it need to have a constant flow of fuel thru the return line ? If so I am assuming the blockage would be inside the water separator cause I checked the lines on both sides and it seems to be good.