Thanks for the file. 1. Yes I changed the height of the lever by bending a bit the tip that lifts the neddle. But as I said before, this is what I did just before putting the old set back. I did not make any changes now when I tested the mylar diaphragms. The reason I did this is because adjusting the lever screw did not make any difference. When I pressed the spring down, the needle wasn't getting lifted. Probably the previous owner had been playing with it because it looked like the clip of the lever had been bent down. So I brought it up a bit. That is when I got the cutter working continuously for first time. It just happens that I had also put back the old pump diaphragm then. Next I just replaced the diaphragm with the mylar types and confirmed they worked too. 2. yes my carburetor has two mixture screws but i didn't touch them at all.