This comprehensive Yanmar 4JH Series workshop service manual provides detailed instructions for maintaining, repairing, and servicing your marine diesel engine. It covers the 4JHE, 4JH-DTE, 4JH-HTE, and 4JH-TE models, offering a wealth of information to empower both experienced mechanics and DIY enthusiasts. The manual is meticulously organized into chapters, each dedicated to a specific aspect of the engine. Detailed illustrations, exploded diagrams, drawings, and photographs guide you through every service repair procedure. Chapter 1 provides an overview of the engine, including exterior views, specifications, construction details, performance curves, cross-sections, dimensions, piping diagrams, and parts interchangeability information. Chapter 2 delves into the basic engine components, exploring the cylinder block, cylinder liners, cylinder head, piston and piston pins, connecting rod, crankshaft and main bearing, camshaft and tappets, timing gear, and flywheel and housing. Chapter 3 focuses on the fuel injection equipment, outlining the fuel supply system, disassembly, reassembly, and inspection of the governor and fuel injection pump, adjustment procedures, the automatic advancing timer, fuel feed pump, fuel injection nozzle, troubleshooting techniques, service data, tools, fuel filter, fuel tank, and design changes in fuel piping lines. Chapter 4 examines the intake and exhaust system, including the intake silencer, intake manifold, turbocharger, mixing elbow, and breather. Chapter 5 explores the lubrication system, covering the lube oil pump, lube oil filter, oil pressure control valve, lube oil cooler, piston cooling nozzle, and rotary waste oil pump. Chapter 6 delves into the cooling water system, outlining the seawater pump, freshwater pump, heat exchanger, pressure cap and sub tank, thermostat, Kingston cock, seawater filter, and bilge pump and strainer. Chapter 7a and 7b provide detailed instructions for the reduction and reversing gear, specifically covering models KBW 20 and 21 and KM4A (angle drive). Chapter 8 focuses on the remote control system, covering installation, inspection, and adjustment procedures. Chapter 9 explores the electrical system, including the battery, starter motor, alternator, instrument panel and wiring codes, warning devices, air heater, electric type stop device, tachometer, and alternator (12V/80A). Chapter 10 concludes the manual with instructions on disassembly and reassembly, including precautions, tools, step-by-step procedures, bolt/nut tightening torque, and test running. This comprehensive manual is an invaluable resource for anyone seeking to maintain, service, or repair their Yanmar 4JH Series marine diesel engine.

The Yanmar 4JH Series, encompassing the 4JHE, 4JH-DTE, 4JH-HTE, and 4JH-TE models, represents a robust and reliable line of marine diesel engines renowned for their performance and durability. These engines power a wide array of vessels, including sailboats, motor yachts, fishing boats, and commercial workboats, catering to diverse marine applications. The 4JH series boasts a displacement of 3.7 liters and employs a four-cylinder, naturally aspirated design, delivering exceptional fuel efficiency and low emissions. Yanmar's commitment to quality engineering is evident in the high-pressure fuel injection system, which ensures precise fuel delivery for optimal combustion and reduced noise levels. Further enhancing their appeal, these engines feature a compact and lightweight design, optimizing space utilization on board and minimizing weight distribution. The Yanmar 4JH series is designed for long-term reliability and ease of maintenance. The engines incorporate advanced features like a robust crankshaft, a balanced reciprocating assembly, and a durable cylinder liner for extended service life. The simplified design allows for easy access to key components, facilitating routine maintenance and repairs. The 4JH Series is also equipped with a comprehensive monitoring system that provides real-time feedback on key engine parameters, enabling proactive maintenance and troubleshooting. This combination of performance, reliability, and user-friendliness has made the Yanmar 4JH Series a popular choice for boat owners and marine professionals seeking a dependable and efficient power source for their vessels.