This workshop service manual provides comprehensive information for the Mercury Mariner SeaPro outboard engine, designed for commercial and heavy-duty marine use. Engineered for reliability and performance, this water-cooled engine delivers 55 horsepower, featuring a robust outboard gearcase with forward, neutral, and reverse gears. Its construction emphasizes durability for demanding applications, ensuring consistent operation in challenging environments. This manual serves as an essential resource for repair and overhaul procedures. It covers critical areas including detailed maintenance schedules, technical specifications, and operational guidance for systems such as ignition, fuel, starting, and trim and tilt. Designed for technicians conversant with general marine practices, this document facilitates the proper upkeep and repair of the Mercury Mariner SeaPro, ensuring its continued optimal performance and longevity.