This comprehensive Yamaha 70HP 90HP 2-stroke Outboard Service Repair Manual covers models manufactured between 1984 and 1996, providing extensive information for repair and maintenance. The manual contains detailed step-by-step instructions, clear illustrations, exploded diagrams, drawings, and photographs, guiding you through every service and repair procedure. It includes special notes, important points, service data, precautions, and torque values for each component. This manual serves as a valuable resource for mechanics and DIY enthusiasts, providing comprehensive explanations of all installation, removal, disassembly, assembly, repair, and check procedures. You will find detailed information on troubleshooting, servicing specifications, tightening torques, checking and adjusting procedures, disassembly and assembly processes, and comprehensive servicing instructions. The manual is organized into groups, covering general information, diagnosis, testing, adjustments, removal, installation, disassembly, and assembly procedures for each system and component. Adjustment and repair operations include reference to wear limits, useful assembly details, and associated service tool numbers with illustrations to ensure accurate usage. To maximize the life of your outboard motor, this manual emphasizes the importance of following maintenance schedules outlined in the periodic maintenance chart. It also stresses the use of genuine Yamaha parts and the importance of keeping thorough records of all maintenance and repairs. This manual is a valuable investment for anyone who owns or works on a Yamaha 70HP or 90HP 2-stroke outboard motor.

The Yamaha 70HP and 90HP 2-stroke outboard motors, produced between 1984 and 1996, represent a significant chapter in the history of Yamaha's marine offerings. These powerful and reliable engines were renowned for their durability, smooth operation, and impressive performance. While the 70HP and 90HP models share a common design foundation, several key differences exist. The 70HP version features a single carburetor, while the 90HP model boasts dual carburetors for enhanced power delivery. Both variants were available with various features, including electric start, power trim and tilt, and remote steering, catering to a wide range of boating needs. These engines were known for their robust construction, incorporating a cast iron powerhead and a reliable ignition system. The 2-stroke design provided a potent power-to-weight ratio, making them ideal for smaller boats. However, the technology was inherently less fuel-efficient than modern 4-stroke motors. The Yamaha 70HP and 90HP 2-stroke outboards were popular with anglers, pleasure boaters, and commercial vessels, offering a balance of performance and affordability. While their production ended in the late 1990s, these engines continue to be sought after by enthusiasts and boat owners who appreciate their classic design and robust performance. The availability of aftermarket parts and a dedicated community of owners ensures that these Yamaha outboards can continue to serve their owners well for many years to come.