Okay...this would be the screw with the spring on it, right? Also, excuse me for being an idiot, lol, but I have some trouble figuring how many parts to parts for oil mixture...can you give me a figure in ounces for a half gallon tank?No, that screw is to drain the carb. the screw you want is just above that and it goes in to up the idle. Way , way too much oil, way too much! Go with 20 parts oil to one part gas.