A friend of mine asked me to look at his L3010. It ran fine at idle but when he would start running the bushbhog after about a minute it would bog down until it was just barely running then then after a minute or so it would raise rpms back up. it would continue to do this even after the bush hog was shut off. He had already changed the fuel filter in the fuel bowl but that had no effect. On the side of the block there was a screw that the fuel supply line to the injection pump ran to and the other end ran to the return line on top of the head. I assume that this is a bleeder of some sort of bleeder and it was a little lose so i tightened it and we thought that corrected the problem, but it came back and he told me it wouldnt idle up again at all now once its starts to die. Im not familiar with these tractors is there another fuel filter somewhere? it the fuel line from the filter runs to the side of the block to what looks like maybe a small diaphram transfer pump before running to the inction pump, is that a transfer pump? Any help would be great thanks.