This manual covers the Mercury Mariner 50 HP 4 Stroke outboard motor, manufactured between 2001 and 2006. This robust 3-cylinder, 4-stroke engine features Electronic Fuel Injection (EFI) and a Capacitor Discharge Ignition (CDI) system, delivering reliable performance for a variety of marine applications. With a displacement of 935cc and a horsepower rating of 50 HP, it is engineered for efficiency and durability, ensuring a dependable boating experience. The purpose of this English-language Service Repair Manual is to provide comprehensive guidance for the maintenance, repair, and troubleshooting of your Mercury Mariner 50 HP 4 Stroke outboard motor. It details essential procedures, technical specifications, and safety recommendations, including lubrication requirements, spark plug gap specifications, and recommended fuel octane. This manual is an indispensable resource for owners and technicians alike, facilitating the proper upkeep and optimal functioning of the outboard motor.