The Briggs & Stratton 591378 Carburetor regulates the fuel and air mixture supplied to the engine for combustion. It meters fuel into the incoming airflow to help create the mixture needed for engine starting and operation. Proper carburetor function supports consistent fuel delivery and smooth engine performance. Replacing a clogged or faulty carburetor can help restore fuel metering... https://www.wholetoolbox.com/briggs-stratton-591378-carburetor/591378.html