1997 Mitsubishi Lancer Air/Fuel Mixture setting

We seem to have the same problem with the 97. In an exploded diagram,the mixture screw you are referring would seem to appear like it's confusing. Is it a an air mix screw or a fuel mix screw. If you are going to some auto sites it will always tell you that whenever the mixture screw is located near the carb air filter then it is presumably an air control screw. If it is located on the base of the carb near the vacuum manifold intake of the engine then it is precisely a fuel controlling screw. With the 97 the mixture screw is only one and located adjacent to the air filter. By the book it can be construed as an air mixture control screw. With common knowledge I presume that an air screw has to be screwed in the direction the way our home clock moves in order to limit the flow of air that will mix in the amount of gasoline charge. With this we are closing in by clockwise the amount of air going inside the carb against the amount of fuel making the intake condition RICH in gasoline. If we turn the air screw counter the way a clock moves then we are opening the way for air to come inside the carb and mix with the amount of gasoline charge in an increased level making the intake condition LEAN in gasoline. I tried LEANING my 97 accordingly and I didn't get a positive result. Perhaps there are other factors that affected the supposed leaning I was expecting like dirty carb and vacuum leaks to name a few. I still need to hear something solid about the purpose of this particular mixture that I mentioned from a knowledgeable person or a mechanic. Someone with integrity has got to verify wither this screw is indeed an air adjust screw or a fuel control screw. I am not sure which way is lean or rich either.