This manual covers the Mercury Mercruiser MCM 3.0L Alpha, powered by a GM 181 CID (3.0L) inline 4-cylinder engine, produced from 1998 onwards, with serial numbers starting from OL010042. This marine engine is engineered for reliable performance, featuring a Mercarb 2 Barrel Carburetor and offering both seawater and closed cooling options. Its robust construction and efficient design make it a dependable choice for various marine applications, reflecting Mercury's commitment to quality and durability. This comprehensive Service Repair Manual in English provides detailed instructions and step-by-step diagrams for workshop procedures. It covers essential areas including general information, maintenance schedules, and troubleshooting guidance for the MCM 3.0L Alpha engine. The manual is designed to assist owners, mechanics, and technicians in effectively maintaining and repairing their vessel, ensuring optimal performance and longevity.