This is referring to the fast idle cam and is used to set cold idle. It is located on right side of th we carb and is interwoven with the choke. Begin with a warmed up engine. Turn off the engine. Open the throttle fully while closing the choke blade. With the choke blade closed, release the throttle. This will put you on the high step of the cam. Start the engine, leave it in park. Yes the engine will be high. Now you can set your fast(cold) idle speed. Using a long skinny screwdriver, you can turn the adjuster till your speed is 2200 rpm. Access to this screw is from the front of the carb. Clockwise to increase, counterclockwise to decrease. Hope this helps.Question, what does it mean when it says "throttle is on the high step of the idle cam" .. do I have to rev the engine to a certain rpm? If so what is it?