This factory service manual covers MerCruiser Stern Drive Units and Marine Engines produced between 1963 and 1973. It details a wide range of MCM and MIE stern drive engines, including models such as MCM 60, MCM 140 (6 Cyl.), MCM 250 (327 CID), MIE 30, MIE 215, and MIE 390, as well as various stern drive units like MCO, MCI, and MC 165. This comprehensive guide is designed to assist users in maintaining and repairing these robust marine powerplants, reflecting MerCruiser's commitment to engineering quality and reliability. The purpose of this manual is to provide detailed service information, step-by-step repair instructions, and essential maintenance specifications. It covers critical areas including general information, removal and installation procedures, electrical systems, fuel systems, engine and drive system overhauls, accessories, and technical specifications. With included illustrations and photos, this resource is an indispensable tool for owners, mechanics, and technicians seeking to ensure the optimal performance and longevity of their MerCruiser equipment through proper maintenance and repair.