Onan MDJE Generator Sets Service Manual • P/N 974-0750, revised December 1985

Onan Marine Diesel Generator Service & Installation Manual (MDJ-Series)

• Covers 1965–1985 Onan Marine Electric Plants and MDJ-Series Diesel GenSet Engines (including 1, 2, and 4-cylinder variants).
• Instant PDF download, fully searchable so you can locate specific part numbers and diagrams in seconds.
• OEM publication P/N 974-0750 (revised December 1985) spanning exactly 100 pages.
• Formatted for standard Letter and A4 printing for easy workshop reference.
• Features 66 technical illustrations, 9 system-specific tables, and complete assembly torque specifications.

Installation & System Overview

This factory service publication delivers the exact technical documentation required for maintaining, repairing, and installing Onan marine diesel generator sets. It eliminates the guesswork from complex marine environments. Inside, you will find specific setup parameters for direct sea water, heat exchanger, and keel cooling configurations. To ensure compliance and vessel safety, the text outlines strict exhaust piping, vibration isolation, and ventilation requirements aligned with Coast Guard and NFPA standards. As a standard workshop practice, always verify current safety protocols and secure all power sources before executing any procedures outlined in the documentation.

Technical Specifications & Maintenance Data

Stop hunting for reliable older specs. This manual provides comprehensive internal engine tolerances, including the precise 97–102 ft.-lb. center main bolt torque for 4-cylinder units. It covers timing procedures across American Bosch, Bryce, and Diesel Kiki injection pumps, detailing port closing marks and precise shim thickness calculations. You also get critical valve clearance data, documented strictly at 0.010–0.017 inches for intake and 0.013–0.017 inches for exhaust, depending on your specific model. From sediment bowl cleaning to raw water pump seal installation, it breaks down the mechanical, electrical, and fuel-injection systems across the entire MDJA, MDJB, MDJC, MDJE, and MDJF marine line.