Fits Black Max Model BM80913 and BM80913A. Must Have 7/8 VERTICAL Crankshaft & 3 Mounting Holes. Might need longer bolts to install on engine. the popular size is 5/16 x 3 1/2 and (2) 5/16 x 2 1/2. They usually mount up fine it just switches the hose hook up point.