One thing I can say is also steer clear of Ryobi as well. I wish I spent proper money and brought a echo/tanaka. My problem seems centered around the walbro wyc carbie which idles ok but has problems with the main mixture being too lean. The only things I can think of causing the problem is either the main jet (which is just a plastic tub), the needle not seating properly ( the needle seems to have a rubber tip on it but looks ok). Which leaves the only thing I can think of trying is readjusting the leaver that the metering diaphram pushes against. What is generally the easiest way to fix problems with these carbies, just throw them away and get a new carb or repair.