A-B1590527-AI ARM-ROCKEROne New Aftermarket Replacement Rocker Arm Fits Briggs and Stratton Small Engines This rocker arm is a valvetrain component Fits Briggs and Stratton (Fits Briggs & Fits Stratton) small engines used in lawn mowers and outdoor power equipment. The rocker arm transfers motion from the pushrod to the intake or exhaust valve, opening and closing the valve as the engine runs. A worn or damaged rocker arm can cause improper valve operation and reduced engine