This comprehensive shop/service/repair manual covers Mercury outboard motors manufactured between 1965 and 1989. Designed for marine propulsion, these 2-stroke engines range from 90HP to 300HP with a 3.4L displacement. The manual provides detailed information for various supported models, ensuring owners and technicians have access to the necessary data for maintaining these reliable marine power units. The purpose of this manual is to serve as a complete guide for the maintenance, repair, and troubleshooting of your Mercury outboard motor. It includes in-depth coverage of routine maintenance, engine removal and installation, fuel systems, lubrication and cooling systems, transmission and drive components, steering systems, intake and exhaust systems, and electrical systems. Advanced troubleshooting sections are also provided to assist in diagnosing and resolving complex issues, empowering users to keep their engines operating at peak performance.