This Service Repair Manual covers the Mercury Marathon outboard, a 15 HP water-cooled engine designed for reliable performance. Built with engineering quality in mind, this model is part of the Marathon Series, intended to provide dependable operation for its users. Its robust construction and specific design features contribute to its reputation for reliability. This manual provides comprehensive coverage for the Mercury Mariner Marathon 15 HP outboard, detailing essential maintenance procedures, troubleshooting guides, and technical specifications. It covers critical systems including the engine, fuel system, ignition, cooling, and lubrication. This guide is an indispensable resource for owners, mechanics, and technicians seeking to maintain, repair, and ensure the optimal performance and longevity of their Mercury Marathon outboard.