This manual covers the Mercury Mariner 25 BigFoot 4-Stroke outboard motor manufactured between 1998 and 2008. Engineered for reliability and performance, the Mariner 25 BigFoot is a robust 4-stroke engine designed to provide dependable power for a variety of marine applications. Its BigFoot designation typically indicates a larger gearcase and lower gear ratio, providing enhanced torque for pushing heavier loads or operating in challenging conditions. This model exemplifies Mercury's commitment to quality marine propulsion. The purpose of this comprehensive service repair manual is to provide detailed information for the maintenance, repair, and troubleshooting of your Mercury Mariner 25 BigFoot outboard. It includes essential technical specifications, step-by-step procedures for routine maintenance and complex repairs, diagnostic guidance for common issues, and clear illustrations, including wiring diagrams and technical drawings. This resource is invaluable for owners, technicians, and mechanics seeking to ensure the optimal performance and longevity of their Mercury Mariner outboard.