This workshop service repair manual covers the Mercury Mariner 40 Marathon outboard engine. Designed for marine applications, this 2-cylinder, 40 horsepower outboard engine is engineered for reliable performance. Its water-cooled system and robust construction ensure durability in demanding aquatic environments. This manual is your definitive guide to understanding and maintaining this powerful marine propulsion unit. The purpose of this comprehensive manual is to provide detailed information for the service, maintenance, and repair of your Mercury Mariner 40 Marathon. It includes essential sections on scheduled maintenance, troubleshooting common issues, and in-depth service procedures. Technical specifications, including details on the gearcase oil capacity and other critical components, are thoroughly explained. This resource is invaluable for owners, technicians, and mechanics seeking to ensure the optimal performance and longevity of their outboard engine.