I changed my fuel filter and loosened the bleed screw on top of the filter. I operate the manual pump priming lever on the fuel pump but I feel no resistance. I rotated the crankshaft clockwise (several times) and pressed the lever after each turn but still no resistance. I removed the fuel filter and confirmed that no fuel was being pushed out by the priming lever. I don't have anyone on board to help with the process so I haven't tried cranking the engine to bleed the lines that way. Any advice?