All 317 pages of this 1985 Yanmar 4JHE Service Manual PDF (OEM #0000A0A1647) focus on tearing down and rebuilding your marine diesel engine, covering the base model plus 4JH-TE, 4JH-HTE, and 4JH-DTE variants. Inside, you get detailed wiring diagrams, complete troubleshooting charts, and step-by-step rebuild procedures for the fuel injection equipment, turbocharger, and marine gear. Open up to massive torque tables, clearance specs, and test values for every major engine system. Verify the turbocharger rotor play wear limit at 0.09 mm and set your injection starting pressure between 195 and 205 kg/cm² before final assembly. Guessing at fuel system specs ruins injectors and wastes shop time. Download the bookmarked file, jump straight to the exact clearance you need, and get your vessel back on the water today.
What's Inside This Yanmar 4JH Series Manual
| System | Pages | Key Topics |
|---|---|---|
| Chapter 1 General | 4-22 | 1.Exterior Views, 2.Specifications, 3.Construction, 4.Performance Curves, 5.Engine Cross Section, 6.Dimensions, 7.Piping Diagrams, 8.Parts Interchangeability |
| Chapter 2 Inspection and Servicing of Basic Engine Parts | 23-54 | Cylinder Block, Cylinder Liners, Cylinder Head, Piston and Piston Pins, Connecting Rod, Crankshaft and Main Bearing, Camshaft and Tappets, Timing Gear |
| Chapter 3 Fuel Injection Equipment | 55-104 | Fuel Supply System, Disassembly, Reassembly and Inspection of Governor, Reassembly and Inspection of Fuel Injection Pump, Fuel Injection Pump and Governor |
| Chapter 4 Intake and Exhaust System | 105-127 | 1.Intake and Exhaust System, 2.Intake Silencer, 3.Intake Manifold, 4.Turbocharger, 5.Mixing Elbow, 6.Breather |
| Chapter 5 Lubrication System | 128-140 | 1.Lubrication System, 2.Lube Oil Pump, 3.Lube Oil Filter, 4.Oil Pressure Control Valve, 5.Lube Oil Cooler, 6.Piston Cooling Nozzle, 7.Rotary Waste Oil Pump (Optional) |
| Chapter 6 Cooling Water System | 141-159 | 1.Cooling Water System, 2.Sea Water Pump, 3.Fresh Water Pump, 4.Heat Exchanger, 5.Pressure Cap and Sub Tank, 6.Thermostat, 7.Kingston Cock (Optional), 8.Sea Water Filter (Optional) |
| Chapter 7 Reduction and Reversing Gear | 160-221 | Marine Gear Model Kbw 20 and 21 (Construction, Installation, Servicing, Operation and Maintenance, Disassembly, Reassembly, Special Tools), Marine Gear Model KM4A |
| Chapter 8 Remote Control (Optional) | 222-228 | 1.Remote Control System, 2.Remote Control Installation, 3.Remote Control Inspection, 4.Remote Control Adjustment |
| Chapter 9 Electrical System | 229-282 | 1.Electrical System, 2.Battery, 3.Starter Motor, 4.Alternator, 5.Instrument Panel and Wiring Codes, 6.Warning Devices, 7.Air Heater (Optional) |
| Chapter 10 Disassembly and Reassembly | 283-316 | 1.Disassembly and Reassembly Precautions, 2.Disassembly and Reassembly Tools, 3.Disassembly and Reassembly, 4.Bolt/nut Tightening Torque, 5.Test Running |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Fuel pump automatic timer box nuts tightening torque | 6.0 ~ 7.0 kg-m (43.39 ~ 50.63 ft-lb) | p. 315 |
| Rotor play in shaft radial direction (Wear limit) | 0.08 (0.0031) mm (in.) | p. 116 |
| Blower blade nut tightening torque | 18 ~ 22 kg-m (1.30 ~ 1.59 ft-lb) | p. 118 |
| Nozzle nut tightening torque | 4 ~ 4.5 kg-m (28.9 ~ 32.5 ft-lb) | p. 94 |
| Injection starting pressure | 195 ~ 205 kg/cm² (2773 ~ 2915 lb/in.²) | p. 95 |
| Back lash (Standard) | 0.04 ~ 0.12 (0.0015 ~ 0.0047) mm (in.) | p. 49 |
| Idle shaft and bushing oil clearance (Standard) | 0.025 ~ 0.075 (0.0009 ~ 0.0029) mm (in.) | p. 50 |
| Fuel feed pump closed off pressure | 0.3 kg/cm² (4.26 lb/in.²) | p. 91 |
| Fuel feed pump tightening torque | 15 ~ 25 kg-cm (1.08 ~ 1.80 ft-lb) | p. 92 |
| Number of cylinders | 4 | p. 8 |
| Fuel injection pressure | 200 ±5 kg/cm² | p. 8 |
| Cylinder head bolt tightening torque (second stage) | 7.5 ~ 8.5 kg-m (54.25 ~ 61.48 ft-lb) | p. 35 |
Yanmar 4JH Series Common Problems This Manual Covers
Yanmar 4JHE engine cranks but will not start or starts intermittently in cold weather. p. 95
Inspect the timing gears and verify alignment marks. Check the idler gear backlash. Replace the gear if the backlash exceeds the standard 0.04 ~ 0.12 (0.0015 ~ 0.0047) mm (in.) shown on page 49. Verify the fuel injection starting pressure is at 195 ~ 205 kg/cm² (2773 ~ 2915 lb/in.²) on page 95.
Manual Section: Fuel Injection Equipment TroubleshootingHeavy exhaust black smoke under load combined with severe loss of power and poor boost. p. 118
Remove the intake piping and inspect the turbocharger rotor for seizure. Check the radial shaft play. During reassembly, torque the blower blade nut to 18 ~ 22 kg-m (1.30 ~ 1.59 ft-lb) as specified on page 118. Clean the turbine chamber thoroughly to prevent further exhaust restriction.
Manual Section: Turbocharger Inspection and TroubleshootingSevere delay in RPM increase and sluggish throttle response when advancing the control lever. p. 91
Check the fuel feed pump operation and internal pressure. Measure the closed off pressure to ensure it meets the minimum 0.3 kg/cm² (4.26 lb/in.²) required on page 91. Torque the fuel feed pump mounting bolts to 15 ~ 25 kg-cm (1.08 ~ 1.80 ft-lb) using the specifications on page 92.
Manual Section: Fuel Injection Pump and Governor AdjustmentEngine temperature rises rapidly at cruising speeds with restricted water flow from the exhaust mixing elbow. p. 146
Inspect the sea water pump impeller and drive gear for severe wear. Verify the pump can maintain the total delivery capacity of 3250 l/h at operational speed, as shown on page 146. Drain the cooling system and clean the heat exchanger tubes to restore proper thermal transfer.
Manual Section: Cooling Water System Component InspectionFrequently Asked Questions
What are the injection timing marks for a Yanmar 4JH-HTE?
For the Yanmar 4JH-HTE engine, the injection timing (FID) is B.TDC 11° ~ 13°. The injection timing is determined by the fuel injection pump pin and rack position. You can find stamped marking lines indicating T.D.C. and fuel injection timing on the flywheel for reference during adjustment.
How do I troubleshoot a Yanmar 4JH-DTE that won’t start?
If a Yanmar 4JH-DTE engine won't start, common causes include no fuel in the tank, a closed fuel tank cock, clogged fuel pipe system or filter element, or air in the fuel pipe. Remedies involve resupplying fuel, opening the cock, cleaning or replacing clogged components, or repairing defective parts like valves or feed pump tappets. For example, if the fuel filter element is clogged, it should be disassembled and cleaned or replaced.
What are the replacement specifications for the turbocharger on Yanmar 4JH engines?
For Yanmar 4JH engines, specific turbocharger models and part numbers are required for replacement. For the 4JH-TE model, the turbocharger is MY20 with Yanmar part number 129492-18000. The 4JH-HTE uses model MY31 (part number 129474-18000), and the 4JH-DTE uses model MY34 (part number 129473-18000).
What is the cylinder head bolt tightening torque for Yanmar 4JH engines?
When assembling the cylinder head on Yanmar 4JH engines, the cylinder head bolts must be tightened in two stages. The first tightening torque is 3.5 ~ 4.5 kg-m (25.32 ~ 32.55 ft-lb), followed by a second tightening torque of 7.5 ~ 8.5 kg-m (54.25 ~ 61.48 ft-lb). This ensures proper sealing and prevents distortion.
How will I receive this Service Manual?
This is a 317-page searchable PDF ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Am I able to print pages from this manual?
Yes, print as many copies as you want, and there are no restrictions. Many mechanics print the section they need and bring it to the shop floor.
Does this Yanmar 4JHE & variants manual include wiring diagrams?
Yes, this Yanmar 4JHE & variants Service Manual includes complete electrical wiring diagrams, wire routing, and connector pinouts.
Document Quality
This is a scanned PDF document, so the text is not searchable or selectable, as it lacks an OCR layer. The text is consistently crisp and easy to read, and all diagrams and illustrations are clear raster images with readable labels. Pages are clean with no significant scan artifacts or marks, and there are no notable blank or filler pages throughout the manual.
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