A-B1797521-AI GEAR-TIMINGOne New Aftermarket Replacement Timing Gear Fits Briggs and Stratton Small Engines This crankshaft timing gear synchronizes the rotation of the crankshaft and camshaft so that the engine valves open and close at the correct times during each cylinder's intake and exhaust strokes. It is a metal replacement for the original plastic gear used in Fits Briggs and Stratton 110P, 111P, and 112P series small gasoline engines commonly found in walk behind lawn