This document provides service information for the 3JH2 series marine diesel engines, including specifications, component diagrams, maintenance procedures, and troubleshooting guides. It has been revised twice to include additional engine models and technical updates. The manual covers general technical details, disassembly and reassembly processes, fuel injection systems, cooling systems, gearboxes, electrical systems, and other relevant topics for servicing these engines.

1. 3JH2 Series
2000. 3. 10
MARINE DIESEL ENGINE
SERVICE MANUAL
0000A0A1015-9112

2. series

3. Publication No. A0A1015
Page No 1
Manual Name Service Manual for Marine Diesel Engine
History of Revision
Engine Model : 3JH2 series
Number of
revision
Reason for
correction
Corrected by
Outline of correction
Date of
revision
Correction item
No. (page)
1st Apr. 2001
2nd Feb. 2003
● Crank shaft
V-pulley bolt
tightening
torque
● Clutch lever
control cable
connectlion.
● Add
the model
3JH25A &
3JH30A
10-32
8-3
1-3, 10-31
Quality
Assurance
Dept.
● Added the standard V-pulley
(material: casting iron) tightening
torque and general use nuts & bolts
tightening torque.
● Added the tightening torque of nut
for the remote control cable connec-
tion of clutch shifting lever.
● Injection timing changed.
● Added the Exterior Views
● Added the Specifieations
● Added the Engine Outiine
● Added the Pertomance Curves
● Added the Piping Diagrams
● Added the Fuel Injection Pump
Sewice Data
● Added the Intake and
Exhaust System figure
● Added the Lubrieation System
figure
● Added the Lube Oil Filter figure
● Added theSea water line flgure
● Added the Marine Gear Models
KM3P1,KM3P3,KM35P1
● Added the Wiring diagrams
1-2-1, 1-2-2
1-3-1, 1-4-1
1-8-1
1-11-1,1-11-2
1-14-1
3-1-1
4-1-1
5-2-1
5-6-1
6-3-1
7-29~7-56
9-4-1
Quality
Assurance
Dept.
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

5. CONTENTS
CHAPTER 1 GENERAL
1.Exterior Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
2.Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
3.Engine Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
4.Performance Curves . . . . . . . . . . . . . . . . . . . . . . . 1-10
5.Piping Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
CHAPTER 2 BASIC ENGINE PARTS
1.CylinderBlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.Cylinder Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
3.Piston and Piston Pins . . . . . . . . . . . . . . . . . . . . . . 2-11
4.Connecting Rod . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
5.Crankshaft and Main Bearing . . . . . . . . . . . . . . . . 2-18
6.Camshaft and Tappets. . . . . . . . . . . . . . . . . . . . . . 2-21
7.Timing Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
8.Flywheel and Housing . . . . . . . . . . . . . . . . . . . . . . 2-26
CHAPTER 3 FUEL INJECTION EQUIPMENT
1.Fuel Injection Pump Service Data . . . . . . . . . . . . . . 3-1
2.Governor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.Disassembly Reassembly and Inspection of Fuel
Injection Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
4.Adjustment of Fuel Injection Pump and Governor . . 3-21
5.Fuel Feed Pump. . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
6.FuelInjection Nozzle . . . . . . . . . . . . . . . . . . . . . . . 3-29
7.Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33
8.Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-35
9.Fuel Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-37
10.Fuel Tank (Optional). . . . . . . . . . . . . . . . . . . . . . . . 3-38
CHAPTER 4 INTAKE AND EXHAUST SYSTEM
1.Intake and Exhaust System . . . . . . . . . . . . . . . . . . 4-1
2.Turbocharger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
3.Mixing Elbow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
CHAPTER 5 LUBRICATION SYSTEM
1. Lubrication System . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
2.Lube Oil Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
3.Lube Oil Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
4.Oil Pressure Control Valve . . . . . . . . . . . . . . . . . . . 5-8
5.Lube Oil Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
6.Piston Cooling Nozzle . . . . . . . . . . . . . . . . . . . . . . 5-10
7.Rotary Waste Oil Pump (Optional). . . . . . . . . . . . . 5-11
CHAPTER 6 COOLING WATER SYSTEM
1.Cooling Water System . . . . . . . . . . . . . . . . . . . . . . 6-1
2.Sea Water Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
3.Fresh Water Pump . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
4.Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
5.Pressure Cap and Sub Tank . . . . . . . . . . . . . . . . . 6-12
6.Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
7.Kingston Cock (Optional) . . . . . . . . . . . . . . . . . . . 6-16
8.Sea Water Filter (Optional) . . . . . . . . . . . . . . . . . . 6-17
9.Bilge Pump and Bilge Strainer (Optional) . . . . . . . 6-18
CHAPTER 7 REDUCTION AND REVERSING GEAR
KM3A
1.Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
2.Shifting Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
3.Inspection And Servicing . . . . . . . . . . . . . . . . . . . . 7-12
4.Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-22
5.Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-25
KM3P1,KM3P3,KM35P1
1.Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29
2.Shifting Device . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-35
3.Inspection And Servicing . . . . . . . . . . . . . . . . . . . . 7-40
4.Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-48
5.Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-53
CHAPTER 8 REMOTE CONTROL
1.Remote Control System . . . . . . . . . . . . . . . . . . . . . . 8-1
2.Remote Control Installation . . . . . . . . . . . . . . . . . . . 8-2
3.Remote Control Inspection . . . . . . . . . . . . . . . . . . . 8-5
4.Remote Control ADJUSTMENT. . . . . . . . . . . . . . . . 8-6
5.Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13
CHAPTER 9 ELECTRICAL SYSTEM
1.Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1
2.Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5
3.Starter Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8
4.Alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-24
5.Instrument Panel . . . . . . . . . . . . . . . . . . . . . . . . . . 9-34
6.Warning Devices . . . . . . . . . . . . . . . . . . . . . . . . . . 9-36
7.Air Heater (Optional) . . . . . . . . . . . . . . . . . . . . . . . 9-39
8.Electric Type Engine Stop Device (Optional) . . . . . 9-40
9.Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-42
10.AIternator 12V/80A(Optional) . . . . . . . . . . . . . . . . . 9-45
CHAPTER 10 DISASSEMBLY AND REASSEMBLY
1.Disassembly and Reassembly Precautions . . . . . . 10-1
2.Disassembly and Reassembly Tools . . . . . . . . . . . 10-2
3.Disassembly and Reassembly . . . . . . . . . . . . . . . . 10-9
4.Bolt/nut Tightening Torque. . . . . . . . . . . . . . . . . . 10-32
5.Test Running . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-33
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

9. 1-2-1
3JH2 Series
Chapter 1 General
1. Exterior Views
1-3 3JH25A/30A
With KM3P3
Operating side
Operating side
Fuel injection pump
Air intake manifold
Mist separator
KM3P3
Torque limiter
Dipstic (clutch side)
Dipstic (engine side)
Lube filter
Fuel priming pump
Fuel filter
Fresh water pump
Alternator
Pressure cap
Fresh water tank
Exhaust manifold
Mixing elbow
Clutch handle
Starting motor
Seawater pump
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

10. 1-2-2
3JH2 Series
Chapter 1 General
1. Exterior Views
With KM3P1/ KM35P1
Operating side
Operating side
Fuel injection pump
Air intake manifold
Mist separator
KM3P1
KM35P1
Dipstic (clutch side)
Dipstic (engine side)
Lube filter
Fuel priming pump
Fuel filter
Fresh water pump
Alternator
Pressure cap
Fresh water tank
Exhaust manifold
Mixing elbow
Clutch handle
Starting motor
Seawater pump
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

12. 3JH2 Series
Chapter 1 General
2. Specifications
1-3-1
Model Unit 3JH25A
Vertical 4-cycle water cooled diesel engine
Direct injection
Normal aspiration
3
82 × 86
1.303
3JH30A
___
___
___
___
mm
m/sec. 9.5 8.6
kW(PS)/rpm
20.2/3300
(27.5/3300)
24.3/3000
(33.0/3000)
0.539 (5.50) 0.713 (7.27)
9.2
18.1
1 — 3 — 2 — 1
YPES-CL
19±1
19.6±0.5(200±5)
Hole type
At Flywheel side
Forced lubrication with trochoid pump
DC 12V-1.8kW
12V-35A
730
185
770
190
545
680
0.9 / 7.0
4.4
0.8
Constant high temperature fresh water cooling
Fresh water : Centrifugal pump
See water : Rubber impeller pump
Counter-clock wise
viewed from stern
8.3
18.4/3200
(25/3200)
22.1/2900
(30/2900)
0.506 (5.016) 0.670 (6.83)
MPa(kgf/cm2)
Type
Combustion system
Aspiration
Number of cylinders
Bore × stroke
Displ acement
Compression ratio
Fire order
Fuel injection pump
Fuel injection timing (b.T.D.C.)
Fuel injection pressure
Fuel injection nozzle
Power taka off
Lubrication system
Engine weight without marine gear (dry)
Lubricating oi l capacity Effect/max.
Starting system
Dimensions
(with KM35P1)
Cooling water
capacity
(Fresh water)
Starting motor
AC generator
Overall length
Overall width
Overall height
Fresh water tank
Sub tank
Cooling system
Direction of rotaion (Crankshaft)
One hour rating
output
(DIN6270B)
flywheel output
Continuous rating
output
(DIN6270A)
flywheel output
Output/crankshaft speed
Brake mean effective
pressure
Piston speed
m/sec.
___
___
___
degree.
MPa(kgf/cm2)
___
___
___
V-kW
V-A
mm
mm
mm
kg
___
___
kW(PS)/rpm
MPa(kgf/cm2)
Output/crankshaft speed
Brake mean effective
pressure
Piston speed
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

14. 3JH2 Series
1-4-1
Chapter 1 General
2. Specifications
marine gear
system
Model KM3P1
12
kg
Not Eqipped
Cone clutch
2.36 / 3.1 6
Clock wise
0.3 / 0.35 0.45 / 0.5
SAE #30
API CC or CD
KM3P3
15
Eqipped
KM35P1
12
Eqipped
Clutch Type
mas
Torque limiter
Reduction ratio
(Forward/Reverse)
Direction of rotation(Forward)
viewed from stern
Lubricating oil capacity
min/max
Lubricating oil
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

19. 442.5
JOINT φ8 FOR FO RETURN
JOINT φ8 FOR FO INLET
28.8
701.3
730.1
180.6
183.8
AHEAD
ASTERN
309.1
MIXING ELBOW PT 11/4
237.5
680
33.5
31.5
6.5
4.5
SOLE
PLATE
543
278 265
190.5
93 95
480
119.5
SEA WATER INLETφ26
7
φ
50
＋0.025
0
φ
22
7.5
4-φ10.5
4-φ
11
73
11 3
φ
52
φ
40
φ
100
φ
50
0
−0.019
pcφ78
pcφ78
φ
100
35
(PROPELLER SHAFT COUPLING) (OUTPUT SHAFT COUPLING)
4
4-M8 TAPPEDHOLES
(DEPTH 12)
p
c
φ
8
2
.
5
DIRECTION OF ROTATION
DETAIL OF PULLY
(VIEW FROM ARROW A)
530
240
240
247.5
22
5
φ
63.5
＋0.048
0
φ
134
445
70 4-φ
16.5
50
305 159
237.3
(VIEW FROM ARROW B)
1-8-1
3JH2
Series
Chapter
1
General
3.
Engine
Outline
3JH25A/30A
Printed
in
Japan
A0A1015-0302
Printed
in
Japan
A0A1015-0302

23. 1-11-1
3JH2 series
Chapter 1 General
4. Performance Curves
3JH25A Performance Curve
Crankshaft speed (min-1)
Specific fuel consumption
Specific
fuel
consumption
(g/kW-h)
Exhaust Gas Temp.
Propeller curve curve
Propeller
power
curve
(kW)
350
300
250
200
150
400
20
15
10
5
0
1500 1700 1900 2100 2300 2500 2700 2900 3100 3300
Crankshaft speed (min-1)
1500 1700 1900 2100 2300 2500 2700 2900 3100 3300
Crankshaft speed (min-1)
1500 1700 1900 2100 2300 2500 2700 2900 3100 3300
350
300
250
200
150
100
400
Exhaust
Gas
Temp.
(°C)
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

24. 1-11-2
3JH2 series
Chapter 1 General
4. Performance Curves
3JH30A Performance Curve
Crankshaft speed (min-1)
Specific fuel consumption
Exhaust Gas Temp.
Propeller curve curve
Propeller
power
curve
(kW)
Specific
fuel
consumption
(g/kW-h)
300
250
200
150
350
20
15
10
5
0
1500 1700 1900 2100 2300 2500 2700 2900 3100
350
300
250
200
150
100
400
Exhaust
Gas
Temp.
(°C)
25
Crankshaft speed (min-1)
1500 1700 1900 2100 2300 2500 2700 2900 3100
Crankshaft speed (min-1)
1500 1700 1900 2100 2300 2500 2700 2900 3100
Printed in Japan
A0A1015-0302
Printed in Japan
A0A1015-0302

27. Thank you very much
for your reading.
Please Click Here
Then Get More
Information.