This manual covers Yamaha 2-stroke outboard motors from the 1983 to 1987 model years, specifically the 150HP, 175HP, 200HP, and 220HP variants. These engines are designed for marine propulsion and are known for their reliable internal combustion engine performance. This document provides comprehensive information to ensure optimal operation and longevity of your Yamaha outboard motor. The purpose of this manual is to serve as a complete resource for owners, mechanics, and technicians. It details essential maintenance procedures, troubleshooting steps, technical specifications, and safety guidelines. Covered topics include general information, routine maintenance, engine and fuel systems, lubrication, cooling, transmission, steering, electrical systems, and advanced troubleshooting, enabling effective repair and upkeep of the specified Yamaha outboard motor models.