Lets see, your carb is a copy of a Carter AFB I think…It has main jets and metering rods that can be changed. After you learn how the carburetor meters fuel into the engine, you can start experimenting with the jets and needles and perhaps improve your mileage a little. Part of this process is learning how to read spark plugs so you know when you have reached the lean limit. If you over-due it, bad things can happen (burned exhaust valves) so knowledge is important here…