This manual covers the Mercury 75 US / 80 EU Four Stroke EFI outboard engines. These engines are designed for reliable performance and efficiency, featuring Electronic Fuel Injection (EFI) for optimal power delivery and fuel economy. The robust construction and water-cooled system ensure durability across various operating conditions. This service repair manual provides comprehensive information for maintaining and servicing these models. This English-language Service Repair Manual is designed to assist owners, technicians, and mechanics in understanding and performing all necessary maintenance and repair procedures. It includes detailed sections on scheduled maintenance, fluid capacities, lubrication, storage, part replacement, and corrosion control. Furthermore, the manual offers in-depth troubleshooting guides for both computer-assisted and manual diagnostics, along with extensive technical specifications covering engine components, systems, and operational theories. Information on propeller selection and engine break-in procedures is also included to ensure optimal performance and longevity of your Mercury engine.