This manual covers Mercury Mercruiser 7.4L and 8.2L GM V8 marine engines, specifically the Gen. VI and L-29 models. These powerful engines feature Multi-Port Fuel Injection (MPI) and are designed for marine applications, offered in Sterndrive (MCM) and Inboard (MIE) configurations. The 7.4L engine has a displacement of 454 cubic inches (CID), while the 8.2L engine displaces 502 cubic inches (CID). This manual is intended for DIY enthusiasts and experienced mechanics seeking to understand and maintain these robust marine powerplants. The Mercury Mercruiser Service and Repair Manual provides comprehensive guidance for the maintenance, troubleshooting, and repair of these engines. It includes detailed instructions for engine removal and installation, analysis of the multi-port fuel injection system, and information on starting, ignition, charging, instrumentation, and power steering systems. Furthermore, the manual details the Velvet Drive Transmission, drive systems, drive shafts, and propeller shafts. With over 1000 pages, it features detailed illustrations, pictures, and diagrams, along with electrical wiring diagrams, to assist users in all aspects of engine care.