Getting your marine diesel back on the water requires the right factory data, which is why this 406-page Yanmar 4JH2-TE service manual PDF (OEM #A0A1029-0104) breaks down the entire 4JH2E engine family, including the HTE and DTE variants. Open to the electrical section to find complete wiring diagrams and warning device diagnostics. You also get detailed teardown procedures for the fuel injection pump, cooling water system, and reduction gear, plus pages of troubleshooting flowcharts for tracking down engine faults. Confirm your main bearing oil clearance is within the standard 0.038 to 0.093 mm before torquing the cap bolts to 83.16 ft-lb. A blown head gasket mid-season is bad enough without guessing at clearances. Download this bookmarked file right to your tablet, jump straight to the specs you need, and start wrenching.
What's Inside This Yanmar 4JH2 Series Manual
| System | Pages | Key Topics |
|---|---|---|
| History of Revision | 3 | Injection Timing Changed, Tightening Torque of Bolts and Nuts for General Use, Tightening Torque of Nut for Remote Control Cable Connection of Clutch Shifting Lever |
| Chapter 1 General | 6-32 | 1. Exterior Views, 2. Specifications, 3. Construction, 4. Performance Curves, 5. Engine Cross Section, 6. Dimensions, 7. Piping Diagrams |
| Chapter 2 Inspection and Servicing of Basic Engine Parts | 33-64 | 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 | 65-163 | Fuel Injection Pump Service Data, Governor, Disassembly, Reassembly and Inspection of Fuel Injection Pump, Fuel Injection Pump and Governor, Fuel Feed Pump, Fuel Injection Nozzle |
| Chapter 4 Intake and Exhaust System | 164-182 | 1. Intake and Exhaust System, 2. Turbocharger, 3. Mixing Elbow |
| Chapter 5 Lubrication System | 183-195 | 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 | 196-214 | 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) |
| Chapter 7 Reduction and Reversing Gear | 215-303 | Construction, Installation, Operation and Maintenance, Servicing, Disassembly, Reassembly, Special Tools, Shifting Device |
| Chapter 8 Remote Control (Optional) | 304-310 | 1. Remote Control System, 2. Remote Control Installation, 3. Remote Control Inspection, 4. Remote Control Adjustment |
| Chapter 9 Electrical System | 311-368 | 1. Electrical System, 2. Battery, 3. Starter Motor, 4. Alternator, 5. Instrument Panel, 6. Warning Devices, 7. Air Heater (Optional) |
| Chapter 10 Disassembly and Reassembly | 369-404 | 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 |
|---|---|---|
| Oil pressure control valve regulating pressure | 3.5 ~ 4.5 kg/cm² (49.78 ~ 64.00 lb/in.²) | p. 191 |
| Main bearing cap bolt tightening torque | 10.5 ~ 11.5 kg-m (75.92 ~ 83.16 ft-lb) | p. 55 |
| Main bearing oil clearance (Crank journal and bushing oil clearance) | Standard: 0.038 ~ 0.093 mm (0.0014 ~ 0.0036 in.), Wear limit: 0.25 mm (0.0098 in.) | p. 54 |
| Connecting rod bolt tightening torque | 5.0 ~ 5.5 kg-m (36.15 ~ 39.77 ft-lb) | p. 51 |
| Oil pressure alarm operating pressure | 0.1 ~ 0.3 kg/cm² (1.422 ~ 4.266 lb/in.²) | p. 350 |
| Fuel Injection Pump Injection Starting Pressure | 195 ~ 205 kg/cm² | p. 66 |
| Lube Oil Filter Discharge Volume | 30 L/min | p. 189 |
| Oil Pressure Regulating Pressure | 3.5 ~ 4.5 kg/cm² | p. 191 |
| Thermostat Opening Temperature | 75 ~ 78°C | p. 210 |
Yanmar 4JH2 Series Common Problems This Manual Covers
Yanmar 4JH2 series alarm sounds while running under load with low oil pressure at idle. p. 191
Measure the oil pressure control valve regulating pressure. Verify it reaches 3.5 ~ 4.5 kg/cm² as shown on page 191. If pressure drops, inspect the main bearing crank journal oil clearance. Replace bearings if clearance exceeds the 0.25 mm wear limit on page 54.
Manual Section: Chapter 5 Lubrication SystemEngine knocks heavily under load and the exhaust contains excessive black smoke during normal acceleration. p. 66
Test the fuel injection pump starting pressure. Check the specifications on page 66 and verify the pressure is between 195 ~ 205 kg/cm². If the pressure is low, remove the pump for servicing. Adjust the injection timing to ensure smooth operation across the RPM range.
Manual Section: Chapter 3 Fuel Injection EquipmentWater temperature warning lamp stays illuminated and engine runs hot during extended operation. p. 210
Drain the coolant and remove the thermostat housing. Inspect the thermostat operation in a heated water bath. Confirm the opening temperature falls exactly between 75 ~ 78°C as specified on page 210. Replace the unit if it fails to open fully or sticks closed.
Manual Section: Chapter 6 Cooling Water SystemInsufficient output and rough running with excessive blow-by from the crankcase breather tube. p. 36
Remove the cylinder head and measure the cylinder bore diameter. Check page 36 to verify the bore does not exceed the 82.06 mm wear limit. Inspect the first piston ring gap. Replace the rings if the gap is larger than the 1.5 mm wear limit on page 46.
Manual Section: Chapter 2 Inspection and Servicing of Basic Engine PartsFrequently Asked Questions
How do I reset a Yanmar 4JH2E/4JH2-TE/4JH2-HTE/4JH2-DTE?
The manual does not describe a general 'reset' procedure for the engine or its alarms. Instead, it provides specific troubleshooting steps and remedies for various malfunctions, such as cleaning, repairing, or replacing components, rather than a single reset action.
What are the torque specs for Yanmar 4JH2E head bolts or injector bolts?
The tightening torque for cylinder head bolts (M10 x 1.25) is 52.4 ~ 69.6 kg-m (37.9 ~ 50.4 ft-lb). For fuel injection nozzle tightening, the torque is 2.0 ~ 3.0 kg-m (14.5 ~ 21.7 ft-lb).
What does the Yanmar 4JH2 error code / alarm mean?
The manual describes two main warning devices: an oil pressure alarm and a cooling water temperature alarm. The oil pressure alarm activates if engine oil pressure drops below 0.1 ~ 0.3 kg/cm² (1.42 ~ 4.26 lb/in²), while the cooling water temperature alarm activates when the temperature reaches a specified high level.
How do I bleed fuel on a Yanmar 4JH2 engine after maintenance?
To bleed the fuel system, first loosen the air-vent screw on the fuel oil filter and pump the priming lever until no air is observed, then tighten the screw. Next, loosen the hexagonal bolt on the fuel pump and pump the priming lever again to vent air, then tighten the bolt. Finally, vent air from the fuel injection piping by loosening the pipe nipple on the injection valve side, with the control handle at intermediate speed and knob switch ON, repeating as necessary before tightening the nipple.
How will I receive this Service Manual?
This is a 406-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.
Can I print specific sections of this Service Manual?
No restrictions at all. Print individual pages, full chapters, or the entire manual. The PDF is completely unlocked.
Does this Yanmar 4JH2E & variants manual include wiring diagrams?
Included. The Yanmar 4JH2E & variants Service Manual covers complete wiring harness diagrams, electrical circuits, and connector pinouts.
Document Quality
This is a scanned document with an OCR layer, so you can search the full text and copy content. The text is crisp and consistently readable throughout. Diagrams and illustrations are clear raster images, with all labels easily legible. Pages are generally clean, with minimal scan artifacts or marks, and no skewed pages. There are no notable blank or filler pages.
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