This workshop service repair manual covers the Mercury Mariner Marathon 55 outboard motor. Designed for marine propulsion, this 55 HP engine utilizes a CDI ignition system and a carburetor for fuel delivery, operating with a water-cooled system. Its robust engineering is intended to provide reliable performance on the water. This comprehensive English-language manual is designed for mechanical technicians. It provides detailed information on maintenance procedures, including lubrication with 2-stroke outboard oil, and troubleshooting. Key technical specifications and guidelines are included to assist in the proper upkeep and repair of the Mercury Mariner Marathon 55, ensuring its continued operational efficiency.