This Service Repair Manual covers Mercury Mariner outboard engines, specifically models 45 Jet, 50, 55 (including Marathon and SeaPro variants), and 60 (including Big Foot, Marathon, and SeaPro variants). These engines, ranging from 45 to 60 horsepower, feature robust construction and are designed for reliable performance. They incorporate advanced systems such as carburetion, fuel pumps, oil injection, and electrical ignition, along with electric starting and charging systems. The manual details various lower unit configurations, including standard gear housings, specialized 60 Big Foot and SeaPro/Marathon housings, and jet drive systems, ensuring comprehensive coverage for diverse operational needs. This manual provides essential information for the maintenance, repair, and troubleshooting of your Mercury Mariner outboard engine. It includes detailed procedures for all major engine components, from the powerhead and mid-section to the lower unit and clamp brackets. Coverage extends to critical systems like power trim, manual tilt, starting, ignition, and fuel delivery, as well as steering, throttle, and shift cables. With comprehensive maintenance schedules, diagnostic guidance, technical specifications, and clear diagrams, this manual serves as an indispensable resource for owners and technicians aiming to ensure optimal engine performance and longevity.