This manual covers the Mercury Mariner 4 HP outboard engine. Designed for reliable performance, this water-cooled, single-cylinder, 4-stroke engine delivers 4 horsepower. Its robust construction and efficient design make it suitable for a variety of marine applications where dependable power is essential. The outboard gearcase features forward, neutral, and reverse gears with shaft drive, ensuring versatile operation on the water. This Service Repair Workshop Manual provides comprehensive guidance for the maintenance and repair of your Mercury Mariner 4 HP outboard. It details essential procedures, including lubrication requirements, fuel specifications, and scheduled maintenance tasks such as spark plug replacement and cooling system upkeep. By following the instructions and technical specifications outlined within, owners and technicians can ensure optimal performance, longevity, and safety of the marine engine.