This series used both Briggs and Kholer Command engines. The ones with Briggs engines sometimes use 28P777-0644. The oil filter is mounted back underneath the carburetor. Most engines this size have the oil filter sticking straight out from the oil pan and it interferes with the frame. Others may use 31G777-0115. If you have an electric clutch, you will have to use the alternator and regulator off of your old engine. If you have a fuel tank or fuel pump mounted to your engine you will also have to use it off of your old engine