This manual covers the Mercury MerCruiser 7.4L / 8.2L GM-V8 marine engines, specifically the Gen V and Gen VI generations. These V-8 engines, available in 7.4L (454 CID) and 8.2L (502 CID) displacements, are engineered for robust performance in marine applications. They feature various fuel system options including Carburetor, EFI, EFI/MP, and MPI. The engines are designed for reliability and are compatible with Velvet Drive Transmissions and drive systems such as Stern Drives (Bravo, Bravo Three) and Inboard Engines. The purpose of this Service and Repair Manual is to provide comprehensive guidance for the maintenance, troubleshooting, and repair of these Mercury MerCruiser engines. It includes detailed, step-by-step instructions with accompanying pictures and diagrams for repair procedures. Key areas covered include routine maintenance, electrical systems (starting, ignition, charging, instrumentation, wiring), fuel systems, cooling systems, exhaust systems, drivetrain components, and steering systems. This manual is an essential resource for owners, mechanics, and technicians to ensure the optimal performance and longevity of their marine engines.