Hyundai Seasall U125S Original operating instructions

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-1-
TABLE OF CONTENTS
ABOUT THIS MANUAL …………………………………………………….…………………
SAFETY PRECAUTIONS……………………………………………………………………
APPROXIMATE CONVERSIONS FROM STANDARD……………………………………..
CHAPTER 1 ENGINE OVERVIEW ………………………………………………………..
1. ENGINE COMPONENTS …………………………………………………
2. ENGINE SUSPENSION……..……………………………………………
3. ENGINE IDENTIFICATION ………………………………………….…..
4. SCHEMATIC DIAGRAM OF COMMON RAIL DIESEL ENGINE ……
5. TECHNICAL DATA ……………………………………………...…..……
6. PERFORMANCE CURVE ……………………………………………..…
7. BELT LAYOUT & ENGINE DIMENSIONS……….……………………
CHAPTER 2 ENGINE MOUNT SYSTEM .………………………………………………
1. ENGINE MOUNTING REQUIREMENTS ………………………....….…
2. MOUNT DIMENSIONS …………………………………………..…….…
3. ENGINE MOUNT TOOL FOR STERNDRIVE MODEL ………….……
CHAPTER 3 COOLING & EXHAUST SYSTEM …………………………………….……
1. SCHEMATIC DIAGRAM OF ENGINE COOLING CIRCUIT ……….…
2. THE FLOW OF SEAWATER ……………………………….……….……
2.1 WATER PICKUP …………………………………..……….……
2.2 SEAWATER STRAINER ………………………..……….…….
2.3 SEAWATER PUMP ……………………………..………………
2.4 SEAWATER DRAIN …………………………..………………..
3. THE FLOW OF ENGINE COOLANT …………………………….………
3.1 ENGINE COOLANT …………………………………………………..…
3.2 REMOVING AIR BUBBLE ………………………………………….…...
3.3 CABIN HEATER CONNECTION …………………………………..……
4. EXHAUST SYSTEM ………………………………………………………
CHAPTER 4 FUEL SYSTEM ………………………………………………………….……
1. THE FLOW OF FUEL ……………………………….……..………………
2. LOW PRESSURE FUEL LINE …………………....…………….…………
3. ACCELERATION SENSOR AND CONTROL LEVER …………………
4. RECOMMENDED FUEL QUALITY ………………....…………….………
5. DRAINING WATER FROM FUEL FILTER ………………………………
CHAPTER 5 AIR INTAKE SYSTEM …………………………………………………………
1. ENGINE ROOM VENTILATION …………………………….…….……
2. AIR FILTER MAINTENANCE ……………………………….…..………
CHAPTER 6 LUBRICATION SYSTEM ………………………………………………….…
1. ENGINE OIL LEVEL CHECKS ………………………………….………
2. RECOMMENDED OIL QUALITY ………………………….…….....……
3. ENGINE OIL EXTACTION PUMP ………………………..………..……
4. OIL FILTER REPLACEMENT …………………………………….………
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INSTALLATION & OPERATION MANUAL
U125 Series Engines
-2-
TABLE OF CONTENTS
CHAPTER 7 ELECTRICAL SYSTEM ……………………………………………………
1. BATTERY CABLE CONNECTIONS …………………………….......…
2. BATTERY CHECKS ………………………………………………….…
3. FUSE AND RELAY ………………………………………………….……
CHAPTER 8 INSTRUMENT SYSTEM ……………………...……………………………
1. INSTRUMENTS CONNECTION …………..………………………...…
2. CUT-OUT FOR GAUGE ……………………...……………………...…
3. CUT-OUT FOR EOI SYSTEM …………………..………………….……
CHAPTER 9 EOI SYSTEM …………………………………………..…………………..
1. OVERVIEW OF EOI SYSTEM ……………………..…………………..…
1.1 INFORMATION LCD ITEM ……………………...……………...…
1.2 SWITCHES ………………………………………......…………..….
1.3 ALARM LAMPS ………………………………………..………...…
2. EOI CONNECTIONS ………………………………………......……..…
3. EOI PIN ASSIGNMENT …………..………………………………........
4. NEUTRAL SWITCH AND DUAL EOI CONNECTION …………….…
5. TRIM WIRING CONNECTION DIAGRAM ………………………...…
6. G-SCAN……………………………………………………………..…….
7. ALARM AND DTC(DIAGNOSIS TROUBLE CODE) ………………….
7.1 ALARM AND DTC(DIAGNOSIS TROUBLE CODE) …………….
7.2 DTC(DIAGNOSIS TROUBLE CODE) LIST………….……………
CHAPTER 10 ANTI CORROSION SYSTEM …………………………………………….
CHAPTER 11 ENGINE OPERATION …………………………………………………..….
1. ENGINE ON/OFF ……………………………………………………….…
2. ENGINE BRAKE IN………………………………………………………
3. EMERGENCY STOP …………………..…………………………….……
CHAPTER 12 ENGINE STORAGE …………………………………………………..……
WINTER STORAGE…………………………………….………………….
CHAPTER 13 MAINTENANCE …………………………………………………………..…
1. THE INITIAL RUNNING CHECK..……………………………….………
2. MAINTENANCE SCHEDULE …………………………………..………
3. STERNDRIVE & TRANSMISSION MAINTENANCE SCHEDULE ….
4. MAINTENANCE LOG……………………………………………………
CHAPTER 14 TROUBLESHOOTING GUIDE ……………………………………………
CHAPTER 15 WARRANTY …………………………………………………………………
WARRANTY REGISTRATION CARD ……………………………..………
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INSTALLATION & OPERATION MANUAL
U125 Series Engines
-3-
ABOUT THIS MANUAL
This engine installation and operation manual is provided as guidance for the installation of
Hyundai SeasAll engine in a boat, and to describe engine operation. Its purpose is to provide
technical information to aid in performing an effective engine installation so as to achieve both
maximum performance and service life. For information on installation, operation and maintenance
of the ZF Marine Transmissions and Sterndrive Bravo Models, please see the separate booklets
included in the original packaging of your Hyundai SeasAll purchase.
Hyundai SeasAll is committed to making clear and accurate information available for those who
maintain, own and repair the U125 Series engines. Hyundai SeasAll values your input regarding
revisions and additional information for our manuals.
WARNING
DEVIATION FROM INSTALLATION INSTRUCTIONS AND OPERATION
GUIDELINES MAY LEAD TO PERSONAL INJURY OR DEATH TO
OPERATORS AND NEARBY PERSONNEL.
CAUTION
DEVIATION FROM INSTALLATION INSTRUCTIONS AND OPERATION
GUIDELINES MAY LEAD TO IMPROPER OPERATION, DAMAGE OR
DESTRUCTION OF THE ENGINE.
The manufacturer is not liable for any damages or losses caused by faulty installation, wrong
handling of the equipment and/or deficient maintenance.
The operator is responsible for the correct and safe operation of the engine and safety of its
occupants and general public.
It is strongly recommended that each operator read and understand this manual before
installing and operating the engine.
This manual as well as safety labels posted on the engine use the following safety alerts to
draw your attention to special safety instructions that should be followed.

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-4-
SAFETY PRECAUTIONS
HOT SURFACES AND FLUIDS
•There is always a risk of burns when working
with a hot engine. Be aware of hot parts like
the turbocharger system, the exhaust system,
hot coolant hoses, etc. Wait until the engine
is fully cool to do inspection and maintenance.
REFUELING
•Refuel only after the engine completely stops.
•Use only the recommended fuel. The wrong
grade of fuel can cause operating problems,
can cause the engine to stop and can cause
engine damage.
•Pay special attention to safe practices when
refueling.
PAINT DAMAGE
•Damage of the engine or parts paint during
maintenance and inspection can cause
corrosion. Any damage must be repainted
after inspection and maintenance.
WELDING ON ENGINE
•Welding directly on the engine block can
cause damage to the engine control systems.
The ECU and related electronic devices must
be disconnected and removed if unavoidable
welding is needed.
.
•Read and understand this operator’s manual
as well as other information supplied by
Hyundai SeasAll for safe use of these
products. Be sure to check your engine
regularly.
•Do not use the engine for a purpose other
than what is intended by Hyundai SeasAll.
Do not modify the performance of the
supplied engine without the express
permission of Hyundai SeasAll. This can be
dangerous, can shorten the life of your
engine and can invalidate your warranty.
•Original and genuine parts supplied from
Hyundai SeasAll must be used for
inspections and maintenance. Hyundai
SeasAll does not guarantee any damage
caused by the use of imitation parts.
•Engine inspection and maintenance should
be carried out by properly trained and factory
approved service engineers.
•The engine should be inspected if the
electronic engine control unit shuts down the
engine.

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-5-
APPROXIMATE CONVERSIONS FROM STANDARD
SYMBOL
MULTIPLY
BY
SYMBOL
SYMBOL
MULTIPLY
BY
SYMBOL
LENGTH
mm
0.039
inch
LENGTH
inch
25.4
mm
cm
0.4
inch
inch
2.54
cm
m
3.28
ft
ft
0.3048
m
AREA
mm2
0.0016
in2
AREA
in2
645.2
mm2
m2
10.764
ft2
ft2
0.093
m2
VOLUME
cm3
0.061
in³
VOLUME
in³
16.388
cm3
mL
0.06
in3
in3
16
mL
Ldm3
61.023
in³
in³
0.016
Ldm3
Ldm3
0.22
imp.gallon
imp.gallon
4.545
Ldm3
Ldm3
0.264
U.S.gallon
U.S.gallon
3.785
Ldm3
m3
0.76
yd3
yd3
1.3
m3
m3
35.315
ft³
ft³
0.028
m3
FORCE
kgf
2.204
lbf
FORCE
lbf
0.453
kgf
N
0.224
lbf
lbf
4.448
N
TEMP.
oF=9/5x℃+32
TEMP.
oC=5/9x(℉-32)
PRESSURE
Bar
14.5
psi
PRESSURE
psi
0.068
Bar
MPa
145
psi
psi
0.0068
MPa
Pa
0.102
mmWc
mmWc
9.807
Pa
Pa
0.004
inWc
inWc
249.098
Pa
KPa
4
inWc
inWc
0.249
KPa
mWg
39.37
inWc
inWc
0.025
mWg
TORQUE
Nm
0.738
lbf ft
TORQUE
lbf ft
1.356
Nm
WEIGHT
kg
2.205
lb
WEIGHT
lb
0.454
kg
kg
35.273
oz
oz
0.028
kg
WORK
kJ/kWh
0.43
BTU/lb
WORK
BTU/lb
2.326
kJ/kWh
MJ/kg
430
BTU/lb
BTU/lb
0.0023
MJ/kg
kJ/kg
0.24
Kcal/kg
Kcal/kg
4.184
kJ/kg
ENERGY
kJ/kg
0.697
BTU/hph
ENERGY
BTU/hph
1.435
kJ/kg
FUEL
CONSUMP.
g/kWh
0.736
g/hph
FUEL
CONSUMP.
g/hph
1.36
g/kWh
g/kWh
0.0016
lb/hph
lb/hph
616.78
g/kWh
FLOW RATE
(GAS)
m3/h
0.588
ft³/min
FLOW RATE
(GAS)
ft³/min
1.699
m3/h
FLOW RATE
(LIQUID)
m3/h
4.403
US gal/min
FLOW RATE
(LIQUID)
US gal/min
0.2271
m3/h
SPEED
m/s
3.281
ft/s
SPEED
ft/s
0.3048
m/s
kph
0.539
knots
knots
1.852
kph
mph
0.869
knots
knots
1.1508
mph
kph
0.62
mph
mph
1.61
kph

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-6-
CHAPTER 1
ENGINE OVERVIEW
ECU Box
Engine Oil Cap
Engine Oil Filter
Seawater Pump
Intercooler
Engine Oil Gauge
Acceleration Lever Sensor
Fuel Filter
VGT
1. Alternator
2. Oil Extraction Pump
3. Air Filter
4. Engine Oil Exchange Button
5. Engine Emergency Stop Button
Injector
Shift Plate
Turbo Heat Protector
Belt-Drive
Coolant Expansion Tank
1.ENGINE COMPONENTS

INSTALLATION & OPERATION MANUAL
U125 Series Engines
- 7 -
•To lift the engine, first remove the engine cover. You will find two engine eyes (see
figure)
•To avoid engine damage, take care that engine lift chains or belts do not hit or touch
surrounding parts during engine lifting.
2.ENGINE SUSPENSION

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-8-
SERIAL NUMBER ON THE ENGINE BLOCK
Engine identification is affixed to the engine block and the ECU box (see figure).
3.ENGINE IDENTIFICATION
•ENGINE NAME PLATE

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-9-
Fuel temperature sensor
pressure limit valve
Glow plug
Coolant temperature sensor
Cam Position Sensor
Crankshaft position sensor Vacuum
modulator
VGT actuator
Rail pressure sensor
Water sensor in fuel
Fuel feed (low) Fuel feed (high) Fuel return
Injector
Intercooler
Common rail
High pressure pump
Main fuel filter
Air filter
ECU
Pump pressure regulator valve
Accel position sensor
Sensor
Actuator
Boost pressure & air temp sensor
Fuel tank
return
return
return
return
4.SCHEMATIC DIAGRAM OF COMMON RAIL DIESEL ENGINE

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-10-
5.TECHNICAL DATA
Engine type
U125S U125P U125J
4-stroke, 16-valve
After-cooled, direct-injection, water cooling
Output ps (kW) 125ps (93)
rpm at full load 4000
Cylinders In-line 4
Ignition sequence 1-3-4-2
Displacement [cm3] 1,582
Bore [mm] 77.2
Stroke [mm] 84.5
Compression ratio 17.3 : 1
Max. torque [kgm]
@ speed [rpm] 26.3 23.5
2000 3700
Injection system Common rail direct injection
Diesel fuel at least CN 51 as per DIN EN 590
Intake air pressure (abs. bar)
@ speed [rpm] 2.5 bar @ 4000 rpm
Coolant quantity (liter) 5.5
Coolant cap opening pressure (bar) 1.1
Engine oil (liter) 5.7
Engine oil pressure (bar) 2~3 at 1800rpm, 100 ℃(oil temp.)
Exhaust gas pressure (kPa) Max. 45
Alternator [A] 130
Engine diagnosis Yes
Weight (kg) 220
Battery capacity (AH) 12V, 150AH recommended
Thermostat opening temp. (℃) 85 (starting to open), 95 (fully open)
Idle rpm warmed up (rev/min) 730
Permissible eng. oil temp (℃) 135
Permissible eng. coolant temp (℃) 105
Propulsion system Sterndrive Shaftdrive Waterjet

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-11-
6.PERFORMANCE CURVE
U125S & U125P MODEL
*BSFC : Brake Specific Fuel Consumption *FC : Fuel Consumption
Torque

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-12-
U125J MODEL
*BSFC : Brake Specific Fuel Consumption *FC : Fuel Consumption

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-13-
7.BELT LAYOUT & ENGINE DIMENSIONS
Bobtail
Front view Side view [for sterndrive]
Side view [for shaftdrive] Side view [for waterjet with bearing housing]
V-RIBBED BELT LAYOUT

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-14-
Front view Side view
ZF 25 A
Front view Side view
MerCruiser Bravo One X Diesel

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-15-
ZF 45 A
Front view Side view
ZF 45 C
Front view Side view

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-16-
CHAPTER 2
ENGINE MOUNT SYSTEM
•The mounts must be strong enough to carry the loads applied by the weight and power of the
engine. It also must be stiff enough that the engine does not sag or move too much when
power is applied.
•The mounts must position the engine at the correct height and angle so that the engine’s
thrust line suits the boat.
2.ENGINE MOUNT DIMENSIONS
1.ENGINE MOUNTING REQUIRMENTS
CAUTION
USE ONLY THE ORIGINAL HYUNDAI SEASALL ENGINE MOUNTS THAT
WERE SUPPLIED WITH THE INITIAL PURCHASE.
AFTER INSTALLATION AND ALIGNMENT OF THE ENGINE, MAKE SURE
THAT NO RESIDUAL TENSION EXISTS IN THE DRIVETRAIN.

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-17-
3.ENGINE MOUNT TOOL FOR STERNDRIVE MODEL
CAUTION
IT IS ESSENTIAL THAT THE ENGINE BED IS PERFECTLY FLAT BEFORE
USING ENGINE MOUNT TOOL.
FOR INFORMATION ON INSTALLATION OF THE STERNDRIVE BRAVO
MODELS, PLEASE SEE THE SEPARATE BOOKLETS INCLUDED IN THE
ORIGINAL PACKAGING OF YOUR HYUNDAI SEASALL PURCHASE.
HYUNDAI SEASALL ENGINES MUST BE USE THE GENUINE ALIGNMENT
TOOL OF HYUNDAI SEASALL OTHER THE DRIVE COUPLER WILL BE
DAMAGED.
Mount hole for U125 model
Mount hole for D170 and D150 model
Mount hole for S250 and S220 model
(O)
(X)
The genuine alignment tool of Hyundai-Seasall(Five step)
The alignment tool of MerCruiser(Four step)

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-18-
CHAPTER 3
COOLING & EXHAUST SYSTEM
1.SCHEMATIC DIAGRAM OF ENGINE COOLING CIRCUIT
IN-MANIFOLD
Pc
COOLANT
PUMP
INTERCOOLER
OIL COOLER
TURBO CHARGER
AIR FILTER
SEA WATER
PUMP
THERMOSTAT
OIL
SEAWATER
INTAKE AIR
EXHAUST AIR
COOLANT ( THERMOSTAT CLOSED & OPENED )
COOLANT (THERMOSTAT OPENED )
SEAWATER
EXPANSION TANK
AIR
ENG.OIL COOLER
HEAT EXCHANGER
EX-MANIFOLD
Ps
CABIN HEATER
CONNECTOR

INSTALLATION & OPERATION MANUAL
U125 Series Engines
-19-
Water strainer ← Water valve ← Water pickup
↓
①Seawater pump
↓
②Intercooler
↓
③Transmission oil cooler
↓
④Heat exchanger
↓
⑤Exhaust elbow
↓
Sea water
2.SEAWATER FLOW –OPEN COOLING CIRCUIT
2.1.WATER PICKUP
•Water pickup should be installed in an area where it won’t pick up air bubbles and will
access clean water during all phases of the engine operation.
•For use in sterndrive models, please see the section “Installing Sterndrive Seawater Pickup”
of the BRAVO MODELS INSTALLATION MANUAL, included in the original packaging.
•For further safety, you can use an additional transom or bottom mounted clamshell-type
water pickup.
2.2.WATER STRAINER
•Strainer should be located in an area where it will
be easily accessible for periodic seawater flow
inspection and cleaning.
•The size of strainer must be of sufficient capacity
to pass the seawater (a flow rate over 150 liters
per minute flow rate).
•Strainer must be installed after water inlet valve in
order to allow user to shut off seawater when
cleaning strainer filter.
CAUTION
IF THE SEAWATER STRAINER IS NOT PROPERLY ASSEMBLED, AIR
CAN BE SUCKED INTO THE COOLING CIRCUIT, DISTURBING THE
VACUUM PROCESS. THIS CAN CAUSE THE ENGINE TO OVERHEAT.