The Makita 038-118-180 Chainsaw Decompression Valve is designed to make engine starting smoother and easier by reducing cylinder compression during ignition. This small yet essential component works by temporarily releasing built-up pressure in the combustion chamber, allowing the starter rope to pull with less resistance. Once the engine fires up, the valve automatically closes, enab... https://www.wholetoolbox.com/makita-038-118-180-chainsaw-decompression-valve