Ford Motorcraft Accelerator pump for Ford Motorcraft 2bbl carburetor. For many model 2100 and 2150 Autolite and Motorcraft carburetors. Ford replacement part covers C4AZ-9B559-A and CM-463. A must have part to cure hesitations in your Ford 2bbl carburetor. There are a few different versions of this pump. The difference is the length of the stem in the middle.