Looking for the factory tear-down steps for your marine engine? This 346-page Yanmar 3jh2-be service manual pdf (OEM #0BJH2-G00101) lays out the entire rebuild process for the 3JH2 series, including the 3JH2-E, 3JH2-TE, 3JH2-TBE, and 3JH25A variants. Inside, you get full disassembly instructions for the KM3A marine gear, detailed fuel injection pump procedures, and step-by-step cooling system overhauls. Open up to complete troubleshooting charts and precise clearance tables to keep your block running perfectly. Verify your lube oil pump outer and inner rotor clearance sits between 0.050 and 0.105 mm, and lock down the cylinder head bolts to exactly 7.5 to 8.5 kg-m on the second pass. Don't risk a blown head gasket on bad forum advice. Grab this bookmarked file, pull it up on your tablet in the engine room, and get the job done right.
What's Inside This Yanmar 3JH2 Series Manual
| System | Pages | Key Topics |
|---|---|---|
| History of Revision | 3 | Exterior Views, Specifications, Engine Outline, Performance Curves, Piping Diagrams, Fuel Injection Pump Service Data |
| General | 5-30 | Exterior Views, Specifications, Engine Outline, Performance Curves, Piping Diagrams |
| Basic Engine Parts | 31-60 | Cylinder Block, Cylinder Head, Pistons and Piston Pins, Connecting Rod, Crankshaft and Main Bearing, Camshaft and Tappets, Timing Gear, Flywheel and Housing |
| Fuel Injection Equipment | 61-100 | 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 |
| Intake and Exhaust System | 101-119 | Turbocharger, Mixing Elbow |
| Lubrication System | 120-133 | Lube Oil Pump, Lube Oil Filter, Oil Pressure Control Valve, Lube Oil Cooler, Piston Cooling Nozzle, Rotary Waste Oil Pump (Optional) |
| Cooling Water System | 134-153 | Sea Water Pump, Fresh Water Pump, Heat Exchanger, Pressure Cap and Sub Tank, Thermostat, Kingston Cock (Optional) |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Cylinder head bolts tightening torque (First) | 3.5 ~ 4.5 kg-m (25.33 ~ 32.56 ft-lb) | p. 39 |
| Cylinder head bolts tightening torque (Second) | 7.5 ~ 8.5 kg-m (54.29 ~ 61.48 ft-lb) | p. 39 |
| Outer rotor and inner rotor clearance (Standard) | 0.050 ~ 0.105 mm (0.0019 ~ 0.0041 in.) | p. 125 |
| Outer rotor and pump body clearance (Standard) | 0.100 ~ 0.170 mm (0.0039 ~ 0.0066 in.) | p. 125 |
| Nozzle opening pressure (Injection starting pressure) | 195 ~ 205 kg/cm² (2,773 ~ 2,915 lb/in.²) | p. 93 |
| Nozzle nut tightening torque | 4 ~ 4.5 kg-m (28.9 ~ 32.5 ft-lb) | p. 92 |
| Thermostat opening temperature | 75 ~ 78 °C (167 ~ 174 °F) | p. 149 |
| Thermostat full open temperature | 90 °C (194 °F) | p. 149 |
| Connecting rod tightening torque | 5.0 ~ 5.5 kg-m (36.15 ~ 39.77 ft-lb) | p. 47 |
| Main bearing cap bolt tightening torque | 10.5 ~ 11.5 kg-m (76.27 ~ 83.15 ft-lb) | p. 51 |
| Cylinder Bore Diameter (Standard) | 82.00 ~ 82.03 mm | p. 34 |
| Governor Weight Nut Tightening Torque | 4.5 ~ 5.0 kg-m (32.54 ~ 36.16 ft-lb) | p. 72 |
Yanmar 3JH2 Series Common Problems This Manual Covers
Yanmar 3JH2 oil pressure alarm sounds after one hour of operation and complete oil loss p. 125
Inspect the lube oil pump assembly for severe internal leaks. Measure the outer rotor and inner rotor clearance as shown on page 125. If the gap exceeds the standard 0.050 ~ 0.105 mm (0.0019 ~ 0.0041 in.), replace the oil pump assembly.
Manual Section: Chapter 5 Lubrication SystemTemperature alarm activates under heavy load and the marine engine overheats rapidly p. 149
Drain the cooling water system and remove the thermostat. Check the thermostat opening temperature on page 149 to verify it opens at 75 ~ 78 °C. Replace the thermostat every year or 2000 hours of operation as detailed on page 150.
Manual Section: Chapter 6 Cooling Water SystemPersistent inability to start or frequent stalling under heavy marine engine load p. 99
Replace the fuel filter element every 300 hours as instructed on page 99 to prevent fuel starvation. Inspect the fuel injection nozzles for clogging. When reassembling, torque the nozzle nut to 4 ~ 4.5 kg-m (28.9 ~ 32.5 ft-lb) according to page 92.
Manual Section: Chapter 3 Fuel Injection EquipmentExcessive engine vibration and unusual internal knocking sounds at high operating RPM p. 51
Check the crankshaft and main bearing clearances. Remove the oil pan and inspect for internal wear. Torque the main bearing cap bolts to 10.5 ~ 11.5 kg-m (75.92 ~ 83.15 ft-lb) as specified on page 51 to eliminate loose mounting noise.
Manual Section: Chapter 2 Basic Engine PartsFrequently Asked Questions
What are the replacement specifications for the Lube Oil Pump assembly?
The manual provides specifications for the lube oil pump, including an engine speed of 3600 rpm, a gear ratio of 28/29 (crank gear/pump gear), and a pump speed of 3477 rpm. For inspection, the standard clearance between the outer rotor and inner rotor is 0.050 ~ 0.105 mm (0.0019 ~ 0.0041 in.), with a wear limit of 0.25 mm (0.0098 in.). The standard clearance between the outer rotor and pump body is 0.100 ~ 0.170 mm (0.0039 ~ 0.0066 in.).
What is the tightening torque for the cylinder head bolts?
When assembling the cylinder head, the cylinder head bolts should be tightened in two steps. The first step requires a torque of 3.5 ~ 4.5 kg-m (25.32 ~ 32.55 ft-lb), and the second step requires 7.5 ~ 8.5 kg-m (54.25 ~ 61.48 ft-lb).
What is the lubricating oil capacity for the marine gear system?
For the KBW10E marine gear model, the lubricating oil capacity is 0.2/0.7 ℓ (12.204/42.714 cu.in.). For the KM3A model, it is 0.05/0.35 ℓ (3.051/21.357 cu.in.). For KM3P1, it is 0.3/0.35 ℓ, and for KM3P3 and KM35P1, it is 0.45/0.5 ℓ.
What is the recommended service interval for replacing the lube oil filter element?
The lube oil filter element should be replaced every 300 hours of engine operation. It is also recommended to replace the filter prior to this if it is very dirty, deformed, or damaged.
What is the wear limit for the cylinder bore diameter?
The standard cylinder bore diameter is 82.00 ~ 82.03 mm (3.2283 ~ 3.2295 in.). The wear limit for the cylinder bore is 82.06 mm (3.2307 in.). If the measurement exceeds this limit, the cylinder block should be replaced.
How will I receive this Service Manual?
This is a 346-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 this manual?
Yes. The PDF has no DRM restrictions, so print any page or section you need for your shop. Works with any standard printer.
Document Quality
This document is a scanned PDF with an OCR layer, allowing you to search and copy text. The text is generally clear and readable, though not as crisp as a native digital document. Diagrams and illustrations are raster images; they are mostly clear and their labels are readable, but they will pixelate if you zoom in closely. Pages are clean with no significant scan artifacts or marks, and are consistently aligned. There are several blank pages used as section breaks throughout the document.
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