Check to make sure there is oil in the tank of your Ryobi chain saw or trimmer.
Put the ignition switch to the "On" position and the choke lever to the "Start" position. Depress the primer bulb five times.
Depress the throttle of your trimmer or chain saw, and then pull your starter rope five or six times or until it sounds like it is trying to run.
Place the choke lever to the "Run" position, and then pull the starter rope until your engine starts.
Insert your screwdriver into the idle-speed screw, which is located to the left and slightly up from the pull rope. If your idle speed has been slow, or if your engine has been stopping frequently while it runs, turn the screw a half-turn to the right, or clockwise. If your idle speed has been running on the high side, turn the screw a half-turn to the left, or counterclockwise.