I just bought a MEP 003 Generator and it works well until I shut the unit down.. If I shut the unit down I have to "push" the diesel through the lines until it starts again. Once it starts it runs like a champ.. I have to bleed the fuel filters and open each injector on top to get the air out. Also when I move the master switch to the run & prime position I don't hear the fuel pump running.. What should I check?