This manual covers Mercury Mercruiser GM V8 Gen. VI Engines, including the 7.4L and 8.2L displacements. These engines feature Electronic Fuel Injection (MPI), Electronic Ignition, and are available with Seawater Cooled or Closed Cooled systems. They are designed for robust performance and reliability in marine applications, paired with various drive options such as Bravo and Blackhawk sterndrives, Velvet Drive and Hurth inboards, and Walter V-Drive systems. Specific models covered include MCM 454 Mag MPI, MCM 502 Mag MPI, MCM 7.4L MPI, MIE 454 Mag MPI Horizon, MIE 8.2L MPI, and MIE 7.4L MPI, with detailed serial number ranges provided for precise identification. This comprehensive Service Repair Manual and Workshop Guide in English provides essential information for maintaining and repairing your Mercury Mercruiser GM V8 engine. It includes detailed procedures for preventative maintenance, servicing, diagnostics, and rebuilds, supported by clear, step-by-step instructions and zoomable illustrations with exploded views. Troubleshooting coverage is extensive, featuring trouble code diagnostics to quickly identify and resolve issues. This resource is invaluable for owners, mechanics, and technicians seeking to ensure the optimal performance and longevity of their marine propulsion system.