Carburetor diaphragm for the Vertical Shaft Lawn Mowers & horizontal shaft 3.5 horsepower to 5 horsepower engines commonly used on GO-KARTS, Minibikes, Tillers, Generators, Water Pumps, Edgers, Etc... This diaphragm replaces part # 270026, 272538, 272637, 4157, 4168. This diaphragm fits 3.5 horsepower models 90200 to 90299 and 91200 to 91299. Also fits 5 horsepower models 133200 to 133299 and 135200 to 135299. If your model number is in between these numbers listed then it is the correct part for you. Part # 530-018 Description Diaphragm Replaces OEM: -BRIGGS & STRATTON: 270026 -BRIGGS & STRATTON: 272538 -BRIGGS & STRATTON: 272538S -BRIGGS & STRATTON: 272637 -BRIGGS & STRATTON: 4157 -BRIGGS & STRATTON: 4168 Fits Models: BRIGGS & STRATTON:--133200, 135200, 136200, 91200 and 92220; for 3 thru 5 HP horizontal Pulsa-Jet engines (new style)