Well Timothy the throttle on a Briggs & Stratton engine is actually actuated by the govenor which is on the side of the engine it has a long thin rod surrounded by a spring which is attached to the govenor lever and the throttle on the carburetor the throttle is activated when you bring the throttle lever to it's notch in the groove you will feel it when the throttle lever hits the notch. then when the engine encounters an obstacle it will automatically idel up or increase in speed. hope this helps you:
Mickey-G
August 2008