1965–1978 Evinrude Outboard Motors 1.5-35 HP Service Manual (P/N 388150)

• Covers 1965–1978 Evinrude outboard motors from 1.5 HP through 35 HP, detailing 2-cylinder, 2-cycle, and electric start configurations.
• Official OEM publication, Part No. 388150, first edition Evinrude service repair handbook.
• Contains 48 exploded views, 9 dedicated electrical wiring diagrams, and comprehensive troubleshooting charts.
• 209-page PDF of technical reference documentation for power head, fuel system, and lower unit maintenance.
• Foundational reference providing essential clearance tables and torque specification charts for late-model 35 HP motors introduced in 1976.

Critical Assemblies & Systems Covered:

• Flywheel magneto ignition systems
• Centri-matic cooling and water pumps
• Manual and electric starter assemblies
• Lower unit gearcases and propeller shafts
• Carburetor and reed valve plates

Step-by-Step DIY Procedures:

• Complete engine repair and power head overhaul
• Breaker point gap adjustment and static timing
• Carburetor synchronization and high-speed tuning
• Decarbonization of the piston crown and cylinder head
• Armature plate and safety switch calibration

Engine and Fuel System Documentation

The documentation provides a structured overview of the power head, fuel system, and electrical components across the 1.5–35 HP range. For a busy marine workshop or the dedicated DIY mechanic, having immediate access to these precise factory tolerances prevents costly dealership visits for standard tune-ups. The manual provides the exact step-by-step procedures and clearance tolerances needed to rebuild the Centri-matic cooling system or synchronize the carburetor linkage, allowing DIYers to confidently complete complex overhauls at the workbench. Chapters explore carburetor operation, detailing the float mechanism, fuel-to-oil mixing ratios, and high-speed needle adjustment for varying altitude conditions. Thorough troubleshooting sections isolate performance issues such as flat spots, power loss, and ignition timing faults using standardized testing techniques. When handling pressurized fuel lines or high-voltage ignition systems, technicians must always verify system depressurization and disconnect power sources prior to maintenance to prevent accidental combustion or injury.

Electrical and Specification Highlights

Wiring diagrams for the Evinrude lineup span manual and electric starter configurations. These include specific pinouts for 12-volt battery connections and alternator output. Engine specifications cover critical bore and stroke data, piston ring gaps, and crankshaft journal clearances found in the comprehensive technical reference data. Torque charts list precise tightening values in both ft-lbs and in-lbs for critical components like flywheel nuts and cylinder head screws. Working on these specific OMC-era outboards comes with a few known repair traps: the original ignition coils located under the flywheel are highly prone to epoxy cracking due to age and heat cycle stress, which causes high-voltage arcing and weak spark; always inspect them closely. Additionally, the aluminum threads in the gearcase and cylinder head strip easily if not step-torqued evenly in thirds, exactly as outlined in the assembly procedures. Battery maintenance sections outline specific gravity thresholds of 1.260–1.280 and charging protocols for the 6N6-3B unit. Whether planning a routine tune-up or evaluating the feasibility of a larger outboard teardown, this reference delivers the exact schematics required to maintain factory structural integrity.