on the very top of your fuel filter there is a small screw type plug that can very slowly be unscrewed, as there is a small hole in the side of this screw, when it is backed out some the air will escape. some models may have two fuel filters. I have some machinery with one and some with two. after the air excapes fuel will begin to flow from this screw plug, then just retighten. this would eliminate your air problem. easily done with just a flat screwdriver.