There are two needle valves on a carb. Turn both just until they are closed. Do not force or you may damage them. Open the high speed needle valve 1-1/2 turns counterclockwise and the idle needle valve one turn. This will give you the initial adjustment so the engine will start and warm up so you can do the final adjustment. You should make sure that the air cleaner is on before you make any adjustments to the carb. To make the final adjustments you will need to move the governor speed lever to the idle position. Set idle speed adjusting screw to get 1750 rpm's. ( you have to hold the throttle lever against the screw while doing this) Turn the idle needle valve in until the rpm's slows or the engine starts to cut out. This is a lean mixture. Then turn it out past where it will idle smoothly. It will run unevenly. Then turn it back so that it is halfway between the two points. Then release the throttle lever. Then do the same with the high speed needle valve with the governor set to the fast position. You do not have to hold the throttle while doing the high speed valve. The engine should run and accelorate smoothly. If not readjust to a slightly richer mixture.