The MTD 951-05118B Carburetor Assembly Primer Hydraulic-175 helps provide consistent fuel delivery for smooth and dependable engine operation. The carburetor mixes fuel with incoming air in the proper proportion for combustion, while the primer assists with supplying fuel during starting. This assembly is designed to support easier engine starts, steady running, and reliable fuel flow... https://www.wholetoolbox.com/mtd-951-05118b-carburetor-assembly-primer-hydraulic-175/951-05118B.html