Briggs & Stratton part 594281 is a genuine OEM carburetor primer bulb. It is a critical component for starting your engine, as it manually pumps fuel into the carburetor to provide a rich fuel-air mixture for cold starts. Product Overview Part Type: Carburetor Primer Bulb (sometimes listed as a “Purge Bulb”). Function: Assists in quicker engine starting by priming the carburetor. Design: Features a standard 1-1/4″ diameter and is made from durable, flexible rubber/plastic to withstand fuel exposure. Common Engine Fits: Specifically designed for newer small vertical shaft engines, including the 300E, 450E, 500E, and 550E series.