Provides service, repair and maintenance information for 1964-1971 Mercury 3.9-135hp outboard models including 1 through 6 cylinder motors. Includes general information about each model, tools and techniques, troubleshooting, lubrication, maintenance and tune-up, timing, synchronizing and adjusting, fuel system, ignition and electrical systems, power head, lower unit, automatic rewind starter, power trim and tilt systems and complete wiring diagrams. Features 296 illustrated pages.