I get asked 20 times a month where to get a carb adjusting tool for weedeater, string trimmers and hand held blowers. This is the most common size. Of course the government does not want you to adjust your carb for fear of messing up the “from factory” emissions. But a lot of the time all you need is an 1/8 turn or so to make your engine run as good as new. Watch the video to see if you have this type of screw on your carb.