This manual covers the Mercury Mariner 20 JET 20 outboard engine. Engineered for reliability and performance, this water-cooled, 2-cylinder, 323 cc (19.7 cubic inches) engine delivers 20 HP (14.9 kW) through a carbureted fuel system and CD ignition. Its robust design, featuring a tiller handle steering and manual tilt with optional power trim, makes it suitable for a variety of marine applications. The outboard gearcase with a 2.15:1 gear ratio and a weight of 45-48 kg ensures efficient power transfer and maneuverability. This Service Repair Workshop Manual provides comprehensive guidance for maintaining and repairing your Mercury Mariner 20 JET 20 outboard. It details essential procedures, including recommended fuel (87 Octane Unleaded Gasoline), spark plug (NGK BUZHU), and gearcase lubricant (Mercury Hi-Performance Gear Lubricant). The manual covers technical specifications, troubleshooting, and operational aspects, empowering owners and technicians to ensure optimal performance and longevity of the engine. This English-language resource is designed to facilitate effective upkeep and repair.