Mercury 90 115hp 6 Inline Crankshaft, pistons, rods, reeds and bearings assy; Fits 1984-88 6 cyl; may fit some 140hp models. Used 436-6646A2 SUPERSEDES TO 436-9072A1. Is serviceable except no; 2 piston & rings. All pistons std size. What you see in pics is what you get. If unsure, please give me your serial no; so I can see if it fits your motor.