Page 1
6SY
series
OPERATION MANUAL
6SY Operation Manual
P/N 0A6301-G0000
MARINE
ENGINES
Page 2
ii 6SY Operation Manual
Disclaimers:
We reserve the right to change specifications and to improve our products without notice
or obligation.
Yanmar and are registered trademarks of Yanmar Co., Ltd. in Japan, the
United States and / or other countries.
All Rights Reserved:
No part of this publication may be reproduced or used in any form by any means - graphic,
electronic, or mechanical, including photocopying, recording, taping, or information
storage and retrieval systems - without the written permission of Yanmar Marine
International.
© 2005 Yanmar Marine International.
Page 3
6SY Operation Manual iii
INTRODUCTION
6SY Operation Manual
Welcome to the world of Yanmar Marine!
Yanmar Marine offers engines, drive
systems and accessories for all types of
boats, from runabouts to sailboats, and
from cruisers to mega yachts. In marine
leisure boating, the worldwide reputation of
Yanmar Marine is second to none. We
design our engines to respect nature. This
means quieter engines, with minimal
vibrations, cleaner than ever. All of our
engines designed after 1996 meet most of
the present and future emission
regulations, such as BSO II, SAV, EPA II,
IMO and RCD.
To help you enjoy your Yanmar 6SY engine
for many years to come, please follow
these recommendations:
• Read and understand this Operation
Manual before you operate the machine
to ensure that you follow safe operating
practices and maintenance procedures.
• Keep this Operation Manual in a
convenient place for easy access.
• If this Operation Manual is lost or
damaged, order a new one from your
authorized Yanmar marine dealer or
distributor.
• Make sure this manual is transferred to
subsequent owners. This manual should
be considered a permanent part of the
engine and remain with it.
• Constant efforts are made to improve the
quality and performance of Yanmar
products, so some details included in
this Operation Manual may differ slightly
from your engine. If you have any
questions about these differences,
please contact your authorized Yanmar
marine dealer or distributor.
• The specifications and components
(instrument panel, fuel tank, etc.)
described in this manual may differ from
ones installed on your vessel. Please
refer to the manual provided by the
manufacturer of these components.
Page 4
INTRODUCTION
iv 6SY Operation Manual
RECORD OF OWNERSHIP
Take a few moments to record the information you need when you contact Yanmar for
service, parts or literature.
Engine Model: __________________________________________________________
Engine Serial No.: _______________________________________________________
Date Purchased:_________________________________________________________
Dealer:_________________________________________________________________
Dealer Phone:___________________________________________________________
Page 5
6SY Operation Manual v
TABLE OF
CONTENTS
6SY Operation Manual
Page
Introduction..................................................................... iii
Table of Contents ............................................................ v
Safety............................................................................... 1
Safety Precautions ..................................................... 2
Before You Operate............................................. 2
During Operation and Maintenance..................... 3
Product Overview ......................................................... 19
Yanmar 6SY Features and Applications .................. 19
NamePlate ............................................................... 21
Engine Nameplate (Typical) .............................. 21
Engine Management System (EMS S6) ............ 23
Rotation Speeds ................................... 24
Redundant Throttle Mode ..................... 24
Coolant Temperature............................ 24
Oil Pressure .......................................... 25
Before You Operate...................................................... 27
Diesel Fuel......................................................... 33
Diesel Fuel Specifications ................................. 33
Additional Technical Fuel
Requirements ....................................... 33
Diesel Fuel Lines .................................. 34
Filling the Fuel Tank .......................................... 34
Bleeding the Fuel System.................................. 36
Page 6
TABLE OF CONTENTS
vi 6SY Operation Manual
Engine Oil ................................................................. 37
Engine Oil Specifications ................................... 38
Service Categories................................ 38
Definitions ............................................. 38
Additional Technical Engine Oil
Requirements:....................................... 38
Engine Oil Viscosity ........................................... 38
Maximum Angles of Inclination During
Operation .............................................. 39
Checking Engine Oil........................................... 39
Adding Engine Oil .............................................. 40
Selection of Marine Gear Oil .............................. 40
Engine Coolant ......................................................... 40
Engine Coolant Specifications ........................... 41
Coolant (Closed Cooling System) ...................... 41
Checking the Coolant Level ............................... 42
Daily Checks............................................................. 44
Visual Checks .................................................... 44
Check Diesel Fuel, Engine Oil, and Engine
Coolant Levels ................................................... 45
Checking and Refilling Marine Gear Oil ............. 45
Checking the Battery Electrolyte Level .............. 45
Checking the Alternator Belt .............................. 45
Checking the Alarm Indicators ........................... 45
Preparing Fuel, Oil and Coolant in Reserve....... 45
Engine Operation .......................................................... 47
Starting Engine ......................................................... 57
Starting at Low Temperatures............................ 57
Shutting Down the Engine.................................. 57
Checking the Engine After Operation ....................... 58
Periodic Maintenance ................................................... 59
Safety Precautions ................................................... 59
Before You Operate ........................................... 59
During Operation and Maintenance ................... 60
Precautions............................................................... 74
The Importance of Periodic Maintenance .......... 74
Performing Periodic Maintenance ...................... 75
The Importance of Daily Checks ........................ 75
Keep a Log of Engine Hours and Daily
Checks ............................................................... 75
Yanmar Replacement Parts ............................... 75
Tools Required................................................... 75
Page 7
TABLE OF CONTENTS
6SY Operation Manual vii
Ask Your Authorized Yanmar
Marine Dealer or Distributor
For Help............................................................. 75
Required EPA Maintenance
USA Only........................................................... 76
EPA Requirements
USA Only........................................................... 76
EPA Requirements................................................... 76
Conditions to Ensure Compliance with EPA
Emission Standards........................................... 76
Inspection and Maintenance.............................. 77
Tightening Fasteners ......................................... 77
Periodic Maintenance Schedule ........................ 78
Engines with Low Operating Hours ................... 78
Inspection and Maintenance of EPA
Emission-Related Parts............................... 80
Periodic Maintenance Procedures..................... 81
After Initial 50 Hours of Operation............... 81
Replace Engine Oil and Engine Oil
Filter Element........................................ 81
Clean the Centrifugal Engine Oil
Cleaner ................................................. 83
Functional Inspection............................ 85
Check and Adjust the Alternator Belt.... 86
Check Electronic Management
System (EMS) Operation...................... 86
Adjust Propeller Shaft Alignment .......... 86
Replace the Closed Crankcase
Ventilation Filter Element...................... 87
Every 50 Hours of Operation....................... 89
Drain or Replace the Fuel Filter
Element and Fuel Filter / Water Separator 89
Check the Battery Electrolyte Level (
Servicable Batteries Only) .................... 91
Every 250 Hours of Operation..................... 93
Adjust the Intake / Exhaust Valve
Clearance ............................................. 93
Check and Adjust the Unit Injector
Rocker Arms ......................................... 93
Drain the Fuel Tank .............................. 93
Check or Replace the Anodes (
Engines with Heat Exchangers)............ 94
Replace the Air Intake Filter ................. 94
Clean the Turbocharger........................ 95
Clean the Charge Air Cooler................. 95
Page 8
TABLE OF CONTENTS
viii 6SY Operation Manual
Check the Wiring Connectors ............... 97
Tighten All Major Nuts and Bolts ........... 97
Check or Replace Flexible Engine
Mounts .................................................. 97
Drain, Flush, and Refill the Engine
Coolant.................................................. 97
Clean the Coolant System .................... 99
Every 500 Hours of Operation ................... 104
Check or Replace the Seawater
Pump Impeller (Engines with Heat
Exchanger).......................................... 104
Every 1000 Hours of Operation ................. 105
Check the Unit Injector Spray
Pattern................................................. 105
Adjust Unit Injectors ............................ 105
Replace Flexible Engine Mounts......... 105
Every 2000 Hours of Operation ................. 105
Overhaul and Check Fuel Feed
Pump................................................... 105
Clean Engine Oil Cooler...................... 105
Check the Battery Charge .................. 106
Replace the Battery............................. 107
Check for Leakage of Fuel, Engine
Oil and Engine Coolant ....................... 108
Clean the Battery ................................ 110
Long-Term Storage..................................................... 113
Specifications.............................................................. 115
Principal Engine Specifications ........................ 115
Page 9
6SY Operation Manual 1
SAFETY
6SY Operation Manual
Yanmar considers safety of great
importance and recommends that
anyone that comes into close contact
with its products, such as those who
install, operate, maintain or service
Yanmar products exercise care,
common sense and comply with the
safety information in this manual and
on the machine’s safety labels. Keep
the labels from becoming dirty or torn
and replace them if they are lost or
damaged. Also, if you need to replace
a part that has a label attached to it,
make sure you order the new part and
label at the same time.
A
This safety alert symbol
appears with most safety
statements. It means
attention, become alert,
your safety is involved!
Please read and abide by
the message that follows
the safety alert symbol.
A DANGER
Danger (the word “DANGER” is
in white letters with a red
rectangle behind it) – indicates
an imminently hazardous
situation which, if not avoided,
will result in death or serious
injury. Danger is limited to the
most extreme situations.
0000001en
A WARNING
Warning (the word “WARNING”
is in black letters with an orange
rectangle behind it) – indicates a
potentially hazardous situation
which, if not avoided, could
result in death or serious injury.
0000001en
Page 10
SAFETY
2 6SY Operation Manual
SAFETY PRECAUTIONS
Before You Operate
A CAUTION
Caution (the word “CAUTION” is
in black letters with a yellow
rectangle behind it) – indicates a
potentially hazardous situation
which, if not avoided, may result
in minor or moderate injury.
0000001en
CAUTION
Caution without the safety alert
symbol indicates a potentially
hazardous situation that can
cause damage to the engine,
personal property and / or the
environment or cause the engine
to operate improperly.
0000001enMarine
CAUTION
NEVER permit anyone to install
or operate the engine without
proper training.
• Read and understand this
Operation Manual before you
operate or service the engine
to ensure that you follow safe
operating practices and
maintenance procedures.
• Safety signs and labels are
additional reminders for safe
operating and maintenance
techniques.
• See your authorized Yanmar
marine dealer or distributor for
additional training.
0000002enMarine
Page 11
SAFETY
6SY Operation Manual 3
During Operation and
Maintenance
A DANGER
EXPLOSION HAZARD!
• Keep the area around the
battery well-ventilated. While
the engine is running or the
battery is charging, hydrogen
gas is produced which can be
easily ignited.
• Keep sparks, open flame and
any other form of ignition away
while the engine is running or
battery is charging.
• Failure to comply will result in
death or serious injury.
0000003en
A DANGER
SCALD HAZARD!
• NEVER remove the coolant
filler cap if the engine is hot.
Steam and hot engine coolant
will escape and seriously burn
you. Allow the engine to cool
sufficiently before attempting
to remove the filler cap.
• Securely tighten the filler cap
after checking the coolant
level. Steam can escape during
engine operation if the cap is
loose.
• Failure to comply will result in
death or serious injury.
0000002enMarine
Page 12
SAFETY
4 6SY Operation Manual
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• When you remove any fuel
system component to perform
maintenance (such as
changing the fuel filter) place
an approved container under
the opening to catch the fuel.
• NEVER use a shop rag to catch
the fuel. Vapors from the rag
are flammable and explosive.
• Wipe up any spills
immediately.
• Wear eye protection. The fuel
system is under pressure and
fuel could spray out when you
remove any fuel system
component.
• Failure to comply will result in
death or serious injury.
0000009en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• NEVER use diesel fuel as a
cleaning agent.
• Failure to comply will result in
death or serious injury.
0000012en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• NEVER remove the fuel cap
with the engine running.
• Failure to comply will result in
death or serious injury.
0000011en
Page 13
SAFETY
6SY Operation Manual 5
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Only use the key switch to start
the engine.
• NEVER jump start the engine.
Sparks caused by shorting the
battery to the starter terminals
may cause a fire or explosion.
• Failure to comply will result in
death or serious injury.
0000004en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Only fill the fuel tank with
diesel fuel. Filling the fuel tank
with gasoline may result in a
fire and will damage the
engine.
• NEVER refuel with the engine
running.
• Wipe up all spills immediately.
• Keep sparks, open flames or
any other form of ignition
(match, cigarette, static
electric source) well away
when refueling.
• NEVER overfill the fuel tank.
• Fill the fuel tank. Store any
containers containing fuel in a
well-ventilated area, away from
any combustibles or sources
of ignition.
• Failure to comply will result in
death or serious injury.
0000005en
Page 14
SAFETY
6 6SY Operation Manual
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Before you operate the engine,
check for fuel leaks. Replace
rubberized fuel hoses every
two years or every 2000 hours
of engine operation, whichever
comes first, even if the engine
has been out of service.
Rubberized fuel lines tend to
dry out and become brittle
after two years or 2000 hours
of engine operation, whichever
comes first.
• Failure to comply will result in
death or serious injury.
0000015en
A DANGER
EXPLOSION HAZARD!
• NEVER check the remaining
battery charge by shorting out
the terminals. This will result in
a spark and may cause an
explosion or fire. Use a
hydrometer to check the
remaining battery charge.
• If the electrolyte is frozen,
slowly warm the battery before
you recharge it.
• Failure to comply will result in
death or serious injury.
0000007en
Page 15
SAFETY
6SY Operation Manual 7
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is extremely
flammable and explosive under
certain conditions.
• When you prime the fuel
system, operate the fuel
priming lever of the
mechanical fuel pump several
times until the fuel filter cup is
filled with fuel.
• NEVER open the air vent valve
while the fuel system is being
primed. The fuel filter has an
internal air bleed port.
• Failure to comply will result in
death or serious injury.
0000016en
A DANGER
CRUSH HAZARD!
• ALWAYS use the engine lifting
eyes when lifting the marine
engine. The lifting eyes are
engineered to lift the weight of
the marine engine only.
• ALWAYS use lifting equipment
with sufficient capacity to lift
the marine engine. Additional
equipment is necessary to lift
the marine engine and marine
gear together.
• NEVER stand under hoisted
marine engine. If the hoist
mechanism fails, the marine
engine will fall on you, causing
serious injury or death.
• Failure to comply will result in
death or serious injury.
0000026en
Page 16
SAFETY
8 6SY Operation Manual
A WARNING
SEVER HAZARD!
• Keep hands and other body
parts away from
moving / rotating parts such as
the flywheel or PTO shaft.
• Wear tight fitting clothing and
keep your hair short or tie it
back while the engine is
running.
• Remove all jewelry before you
operate or service the engine.
• NEVER start the engine in
gear. Sudden movement of the
engine and / or vessel could
cause death or serious
personal injury.
• NEVER operate the engine
without the guards in place.
• Before you start the engine
make sure that all bystanders
are clear of the area.
• Keep children and pets away
while the engine is operating.
• Check before starting the
engine that any tools or shop
rags used during maintenance
have been removed from the
area.
• Failure to comply could result
in death or serious injury.
0000002enMarine
A WARNING
EXHAUST HAZARD!
• NEVER operate the engine in
an enclosed area such as a
garage, tunnel, underground
room, manhole or ship’s hold
without proper ventilation.
• NEVER block windows, vents,
or other means of ventilation if
the engine is operating in an
enclosed area. All internal
combustion engines create
carbon monoxide gas during
operation. Accumulation of
this gas within an enclosure
could cause illness or even
death.
• Make sure that all connections
are tightened to specifications
after repair is made to the
exhaust system.
• Failure to comply could result
in death or serious injury.
0000003en
Page 17
SAFETY
6SY Operation Manual 9
A WARNING
ALCOHOL AND DRUG
HAZARD!
• NEVER operate the engine
while you are under the
influence of alcohol or drugs.
• NEVER operate the engine
when you are feeling ill.
• Failure to comply could result
in death or serious injury.
0000004en
A WARNING
EXPOSURE HAZARD!
• Wear personal protective
equipment such as gloves,
work shoes, eye and hearing
protection as required by the
task at hand.
• NEVER wear jewelry,
unbuttoned cuffs, ties or loose
fitting clothing when you are
working near moving / rotating
parts such as the flywheel or
PTO shaft.
• ALWAYS tie back long hair
when you are working near
moving / rotating parts such as
a flywheel or PTO shaft.
• NEVER operate the engine
while wearing a headset to
listen to music or radio
because it will be difficult to
hear the warning signals.
• Failure to comply could result
in death or serious injury.
0000005enMarine
Page 18
SAFETY
10 6SY Operation Manual
A WARNING
SUDDEN MOVEMENT
HAZARD!
• Be sure the boat is in open
water away from other boats,
docks, and other obstructions
before increasing rpm.
• Failure to comply could result
in death or serious injury.
0000006enMarine
A WARNING
BURN HAZARD!
• Batteries contain sulfuric acid.
NEVER allow battery fluid to
come in contact with clothing,
skin or eyes. Severe burns
could result. ALWAYS wear
safety goggles and protective
clothing when servicing the
battery. If battery fluid contacts
the eyes and / or skin,
immediately flush the affected
area with a large amount of
clean water and obtain prompt
medical treatment.
• Failure to comply could result
in death or serious injury.
0000007en
A WARNING
HIGH PRESSURE
HAZARD!
• Avoid skin contact with high
pressure diesel fuel spray
caused by a fuel system leak
such as a broken fuel injection
line. High pressure fuel can
penetrate your skin and result
in serious injury. If you are
exposed to high pressure fuel
spray, obtain prompt medical
treatment.
• NEVER check for a fuel leak
with your hands. ALWAYS use
a piece of wood or cardboard.
Have your authorized Yanmar
marine dealer or distributor
repair the damage.
• Failure to comply could result
in death or serious injury.
0000008enMarine
Page 19
SAFETY
6SY Operation Manual 11
A WARNING
SHOCK HAZARD!
• Turn off the battery switch (if
equipped) or disconnect the
negative battery cable before
servicing the electrical system.
• Check the electrical harnesses
for cracks, abrasions, and
damaged or corroded
connectors. ALWAYS keep the
connectors and terminals
clean.
• Failure to comply could result
in death or serious injury.
0000009en
A WARNING
WELDING SHOCK
HAZARD!
• Turn off the battery switch (if
equipped) or disconnect the
negative battery cable and the
leads to the alternator when
welding on the vessel.
• Remove the multi-pin
connector to the engine
control unit. Connect the weld
clamp to the component to be
welded and as close as
possible to the welding point.
• NEVER connect the weld
clamp to the engine or in a
manner which would allow
current to pass through a
mounting bracket.
• When welding is completed,
reconnect the leads to the
alternator and engine control
unit prior to reconnecting the
batteries.
• Failure to comply could result
in death or serious injury.
0000117en
Page 20
SAFETY
12 6SY Operation Manual
A WARNING
ENTANGLEMENT
HAZARD!
• Stop the engine before you
begin to service it.
• NEVER leave the key in the key
switch when you are servicing
the engine. Someone may
accidentally start the engine
and not realize you are
servicing it. This could result
in a serious injury.
• If you must service the engine
while it is operating, remove all
jewelry, tie back long hair, and
keep your hands, other body
parts and clothing away from
moving / rotating parts.
• Failure to comply could result
in death or serious injury.
0000010en
A WARNING
BURN HAZARD!
• Wait until the engine cools
before you drain the engine
coolant. Hot engine coolant
may splash and burn you.
• Failure to comply could result
in death or serious injury.
0000016en
A WARNING
BURN HAZARD!
• If you must drain the engine oil
while it is still hot, stay clear of
the hot engine oil to avoid
being burned.
• ALWAYS wear eye protection.
• Failure to comply could result
in death or serious injury.
0000011en
A WARNING
BURN HAZARD!
• Wait until the engine cools
before draining seawater from
the cooling system. Hot
seawater may splash and burn
you.
• Failure to comply could result
in death or serious injury.
0000016enMarine
Page 21
SAFETY
6SY Operation Manual 13
A WARNING
BURN HAZARD!
• Keep your hands, and other
body parts, away from hot
engine surfaces such as the
muffler, exhaust pipe,
turbocharger (if equipped) and
engine block during operation
and shortly after you shut the
engine down. These surfaces
are extremely hot while the
engine is operating and could
seriously burn you.
• Failure to comply could result
in death or serious injury.
0000015en
A WARNING
FIRE HAZARD!
• Undersized wiring systems can
cause an electrical fire.
• Failure to comply could result
in death or serious injury.
0000027en
A CAUTION
COOLANT HAZARD!
• Wear eye protection and
rubber gloves when you
handle Long Life engine
coolant. If contact with the
eyes or skin should occur,
flush eyes and wash
immediately with clean water.
• Failure to comply may result in
minor or moderate injury.
0000005enMarine
A CAUTION
FLYING OBJECT HAZARD!
• ALWAYS wear eye protection
when servicing engine and
when using compressed air or
high-pressure water. Dust,
flying debris, compressed air,
pressurized water or steam
may injure your eyes.
• Failure to comply may result in
minor or moderate injury.
0000003en
Page 22
SAFETY
14 6SY Operation Manual
CAUTION
• Only use diesel fuels
recommended by Yanmar for
the best engine performance,
to prevent engine damage and
to comply with EPA warranty
requirements.
• Only use clean diesel fuel.
• NEVER remove primary
strainer from the fuel tank filler
port. If removed, dirt and
debris could get into the fuel
system causing it to clog.
0000004enMarine
CAUTION
If any problem is noted during
the visual check, the necessary
corrective action should be
taken before you operate the
engine.
0000021en
CAUTION
Be sure to close the seacock.
Neglecting to close the seacock
could allow water to leak into the
boat and may cause it to sink.
0000152en
CAUTION
The illustrations and
descriptions of optional
equipment in this manual, such
as the operator’s console, are for
a typical engine installation.
Refer to the documentation
supplied by the optional
equipment manufacturer for
specific operation and
maintenance instructions.
0000018en
CAUTION
If any indicator illuminates
during engine operation, stop
the engine immediately.
Determine the cause and repair
the problem before you continue
to operate the engine.
0000029en
CAUTION
NEVER hold the key in the
START position for longer than
15 seconds or the starter motor
will overheat.
0000007en
Page 23
SAFETY
6SY Operation Manual 15
CAUTION
Observe the following
environmental operating
conditions to maintain engine
performance and avoid
premature engine wear:
• NEVER run the engine if the
ambient temperature is above
+40°C (+104°F) or below -16°C
(+5°F)
◆ If the ambient temperature
exceeds +40°C (+104°F) the
engine may overheat and
cause the engine oil to break
down.
◆ If the ambient temperature
falls below -16°C (+5°F)
rubber components such as
gaskets and seals will
harden causing premature
engine wear and damage.
◆ See your authorized Yanmar
marine engine dealer or
distributor if the engine will
be operated in either
temperature extreme.
• See your authorized Yanmar
marine dealer or distributor if
you need to operate the engine
at high altitudes. At high
altitudes the engine will lose
power, run rough, and produce
exhaust gases that exceed the
design specifications.
0000065enMarine
CAUTION
• Only use the engine coolant
specified. Other engine
coolants may affect warranty
coverage, cause an internal
buildup of rust and scale
and / or shorten engine life.
• Prevent dirt and debris from
contaminating engine coolant.
Carefully clean the heat
exchanger cap and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine coolants. This may
adversely affect the properties
of the engine coolant.
0000006enTrans
CAUTION
• Only use the engine oil
specified. Other engine oils
may affect warranty coverage,
cause internal engine
components to seize, or
shorten engine life.
• Prevent dirt and debris from
contaminating engine oil.
Carefully clean the oil
cap / dipstick and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine oil. This may adversely
affect the lubricating
properties of the engine oil.
• NEVER overfill. Overfilling may
result in white exhaust smoke,
engine overspeed or internal
damage.
0000005en
Page 24
SAFETY
16 6SY Operation Manual
CAUTION
• NEVER overfill the engine with
engine oil.
• ALWAYS keep the oil level
between upper and lower lines
on the oil cap / dipstick.
0000015en
CAUTION
For maximum engine life,
Yanmar recommends that when
shutting the engine down, you
allow the engine to run, without
load, for five minutes. This will
allow the engine components
that operate at high
temperatures, such as the
exhaust system, to cool slightly
before the engine itself is shut
down.
0000008enYDG
CAUTION
NEVER use an engine starting
aid such as ether. Engine
damage will result.
0000009en
CAUTION
Make sure the engine is installed
on a level surface. If a Yanmar
Marine Engine is installed at an
angle that exceeds the
specifications stated in the
Yanmar Marine Installation
manuals, engine oil may enter
the combustion chamber
causing excessive engine speed,
white exhaust smoke and
serious engine damage. This
applies to engines that run
continuously or those that run
for short periods of time.
0000010enMarine
CAUTION
Be careful not to get any oil on
the belt(s). Oil on the belt causes
slipping and stretching. Replace
the belt if it is damaged.
0000153enMarine
CAUTION
If seawater is left inside of the
engine, it may freeze and
damage parts of the cooling
system when the ambient
temperature is below 0°C (32°F).
0000154en
CAUTION
NEVER allow engine oil or diesel
fuel oil to contact the flexible
rubber mount. Oil makes rubber
deteriorate.
0000155en
Page 25
SAFETY
6SY Operation Manual 17
CAUTION
• ALWAYS be environmentally
responsible.
• Follow the guidelines of the
EPA or other governmental
agencies for the proper
disposal of hazardous
materials such as engine oil,
diesel fuel and engine coolant.
Consult the local authorities or
reclamation facility.
• NEVER dispose of hazardous
materials irresponsibly by
dumping them into a sewer, on
the ground or into ground
water or waterways.
• Failure to follow these
procedures may seriously
harm the environment.
0000013en
CAUTION
Protect the air cleaner,
turbocharger (if equipped) and
electric components from
damage when you use steam or
high-pressure water to clean the
engine.
0000014en
CAUTION
If any indicator fails to illuminate
when the key switch is in the ON
position, see your authorized
Yanmar marine dealer or
distributor for service before
operating the engine.
0000028enMarine
CAUTION
Establish a periodic
maintenance plan according to
the engine application and make
sure you perform the required
periodic maintenance at
intervals indicated. Failure to
follow these guidelines will
impair the engine’s safety and
performance characteristics,
shorten the engine’s life and may
affect the warranty coverage on
your engine.
0000024en
CAUTION
It is important to perform daily
checks as listed in the Operation
Manual.
Periodic maintenance prevents
unexpected downtime, reduces
the number of accidents due to
poor engine performance and
helps extend the life of the
engine.
0000060enMarine
Page 26
SAFETY
18 6SY Operation Manual
CAUTION
If the fuel filter / water separator
is positioned higher than the fuel
level in the fuel tank, water may
not drip out when the fuel
filter / water separator drain cock
is opened. If this happens, turn
the air vent screw on the top of
the fuel filter / water separator
2-3 turns counterclockwise.
Be sure to tighten the air vent
screw after the water has drained
out.
0000025en
CAUTION
• When the engine is operated in
dusty conditions, clean the air
cleaner element more
frequently.
• NEVER operate the engine with
the air cleaner or element(s)
removed. This may allow
foreign material to enter the
engine and damage it.
0000026en
CAUTION
Clean or replace the air cleaner
element if the air intake
restriction exceeds the value
listed in the Operation and
Service Manuals.
0000046enMarine
CAUTION
NEVER turn off the battery
switch (if equipped) or short the
battery cables during operation.
Damage to the electric system
will result.
0000061en
Page 27
6SY Operation Manual 19
PRODUCT
OVERVIEW
6SY Operation Manual
YANMAR 6SY FEATURES
AND APPLICATIONS
The 6SY is a four-stroke 6-cylinder direct
injection diesel engine. The engine is
turbocharged and equipped with a charge
air cooler containing a liquid coolant
system.
The engine has a heat exchanger which is
cooled by a seawater coolant system.
The engine is designed for pleasure craft
use.
The engine must be installed correctly with
coolant lines, exhaust gas lines and
electrical wiring. Any auxiliary equipment
attached to the engine should be easy to
use and accessible for service. To handle
the drive equipment, propulsion systems
(including the propeller) and other onboard
equipment, always observe the
instructions and cautions given in the
operation manuals supplied by the
shipyard and equipment manufacturers.
The laws of some countries may require
hull and engine inspections, depending on
the use, size and cruising area of the boat.
The installation, fitting and surveying of
this engine all require specialized
knowledge and engineering skills. See
Yanmar's local subsidiary in your region or
your authorized Yanmar marine dealer or
distributor.
Page 28
PRODUCT OVERVIEW
20 6SY Operation Manual
COMPONENT IDENTIFICATION
Figure 1 illustrates a typical version of a 6SY engine. Your engine may have different
equipment from that illustrated.
(1)
(16)
(15)
(14)
(13)
(11) (10)
(9)
(8)
(6)
(5)
(4)
(3)(2)
(7)
(12)
(17)
(20)
(21)
(22)
(2
3)
(24)
(25)
(1)
(19)(18)
Figure 1
1. Air Filter
2. Coolant Fill Cap
3. Coolant Recovery Tank
4. Engine Oil Fill Cap
5. Engine Number, Stamped into the
Engine Block
6. Nameplate
7. Coolant Pump
8. Coolant Drain
9. Engine Oil Filter
10. Engine Oil Cleaner
11. Engine Oil Dipstick
12. Engine Oil Drain
13. Heat Exchanger
14. Seawater Outlet
15. Seawater Supply
16. Seawater Pump
17. Charge Air Cooler
18. Close Crankcase Ventilation
19. Turbocharger
20. Fuel Filter
21. Fuel Pump
22. Starter Motor
23. Alternator (1 Standard, 2nd Optional)
24. Engine Oil Pressure Sensor
25. Control Unit (EMS S6)
Page 29
PRODUCT OVERVIEW
6SY Operation Manual 21
NAMEPLATE
The following figure (Figure 2) shows
the location of regulatory and safety
labels on Yanmar 6SY marine engines.
Engine Nameplate (Typical)
6SY Engines
Figure 2
MODEL
CONT. RATING kW rpm
rpm
MAX OUTPUT kW
ENGINE NO.
YANMAR DIESEL ENGINE
0003496
Page 30
PRODUCT OVERVIEW
22 6SY Operation Manual
FUNCTION OF MAJOR COMPONENTS
Name of part Function
Fuel Filter
Removes dirt and water from the fuel. Drain the filter periodically. The filter
element should be replaced periodically. See Drain or Replace the Fuel Filter
Element and Fuel Filter / Water Separator on page 89.
Fuel Feed Pump Pumps fuel from the tank to the fuel injection system.
Engine Oil Fill Port Fill port for engine oil.
Engine Oil Filter
Filters fine metal fragments and carbon from the engine oil. Filtered engine oil is
distributed to the engine's moving parts.
Coolant System
There are two coolant systems: closed cooling with coolant and seawater. The
engine's combustion heat is cooled by the closed cooling circuit. The closed circuit
is cooled by seawater using a heat exchanger. The seawater also cools the
engine / marine gear oil.
Heat Exchanger The heat exchanger cools the closed cooling circuit with seawater.
Closed Cooling Circulation
Pump
The centrifugal water pump circulates coolant inside the engine. The circulating
pump is driven by a belt.
Seawater Pump
The rubber impeller-type pump pumps seawater for cooling. Never operate it
without seawater, as this will damage the impeller.
Coolant Fill Cap
The fill cap on the coolant tank has a pressure regulating valve. When the coolant
temperature rises, the pressure rises inside the fresh water system.
Coolant Recovery Tank
The pressure regulating valve releases vapor and hot water overflow to the
coolant recovery tank. When the engine stops and the coolant cools, the pressure
in the coolant tank drops. The fill cap valve then opens to send water back from
the coolant recovery tank. This minimizes coolant consumption. The closed
cooling system coolant level can easily be checked and refilled in this tank.
Oil Cooler A heat exchanger that cools high temperature engine oil using seawater.
Turbocharger
The turbocharger pressurizes the air coming into the engine. It is driven by a
turbine that is energized by exhaust gases.
Anode
The metal area of the seawater coolant system is prone to electrical corrosion. The
anodes are installed to prevent this corrosion. The anodes are reduced over time
by electrical corrosion and must be replaced before it is completely consumed in
order to ensure that the metal area of the seawater coolant system remains fully
protected.
Nameplates
Nameplates are provided on the engine and the marine gear and have the model,
serial number and other data.
Starter Starter motor for the engine. Powered by the battery.
Alternator Driven by belt and generates electricity and charges the battery.
Page 31
PRODUCT OVERVIEW
6SY Operation Manual 23
ENGINE MANAGEMENT
SYSTEM (EMS S6)
This engine has an Electronic
Management System (EMS) with unit
injectors (PDE) which provide each
cylinder with the right amount of fuel at the
right time in all operating situations.
The EMS system consists of a control unit
(S6) and sensors for speed, charge air
temperature and pressure, coolant
temperature, oil pressure, and throttle
actuation. These sensors constantly send
signals to the control unit. With this input
data and the programmed control
software, the correct fuel amount and
correct injection time are calculated for
each unit injector (PDE) under the specific
operating conditions.
The EMS system sensors are also used to
send signals to the digital display in the
instrument panel.
The control unit constantly checks the
sensors to make sure they are operational.
The control unit contains monitoring
functions to protect the engine in the event
of a fault which would otherwise damage it.
In the event of a fault, an alarm for low oil
pressure or high coolant temperature for
example, the S6 control unit sends a
message to the digital display.
Only authorized personnel are allowed to
carry out diagnostic procedures and
program changes.
The positions of the sensors which send
signals to the control unit are shown
(Figure 3).
Positions of Sensors for EMS with S6
(4)
(3)
(2)
(1)
Figure 3
1. Oil Pressure Sensor
2. Charge Air Temperature and
Pressure Sensor
3. Coolant Temperature Sensor
4. Engine Speed Sensors (2 used)
Page 32
PRODUCT OVERVIEW
24 6SY Operation Manual
Rotation Speeds
Check instruments at regular intervals.
Redundant Throttle Mode
If there is a fault with the normal throttle or
if CAN communication is interrupted, a
redundant throttle system is provided.
In the event of a CAN open circuit or
throttle fault:
• The EMS automatically switches to the
redundant throttle located on the key
switch panel.
• The redundant throttle must be set at
zero to be activated.
• A light will illuminate on the panel
indicating the redundant throttle is
activated.
Coolant Temperature
Normal coolant temperature when the
engine is running is 70° - 90°C
(158° - 194°F).
The EMS / S6 control system has the
following alarm levels:
• If the temperature is high, 98° - 103°C,
(208° - 217°F) for one second, the S6
control will send a CAN message which
activates a warning.
• If the temperature exceeds 103°C
(217°F), a warning is activated.
• A fault code is generated in the control
unit.
After an alarm, approved values must be
registered for more than two seconds
before resetting the alarm.
Excessively high coolant temperature can
damage the engine.
If run for extended periods under an
extremely light load, the engine may have
difficulty in maintaining normal operating
temperature. However, the temperature will
rise to a normal level again when the load
on the engine is increased.
Rotation Speed
0 - 500 rpm Prohibited engine speed,
passed through when stopping
and starting.
500 - 700 rpm Slow idle. Engine idling is
controlled by the EMS / S6
control system.
700 - 2300 rpm Normal operating speed. The
engine operating speed range
is controlled by the EMS / S6
control system.
2400 - 2600 rpm Unsuitable operating speed.
2600 - 3000 rpm Prohibited engine speed.
Page 33
PRODUCT OVERVIEW
6SY Operation Manual 25
Oil Pressure
The EMS has the following alarm levels:
• At a speed of less than 1000 rpm and an
oil pressure of less than 1.0 bar (15 psi)
• At a speed of more than 1000 rpm and
an oil pressure of less than 2.3 bar
(33 psi) for longer than five seconds
The following functions are available if
there is an alarm:
• Alarm which only switches on a warning.
• Alarm which switches on a warning and
reduces torque if this function is
activated (70% of fuel quantity).
• A fault code is generated in the control
unit.
After an alarm, approved values must be
registered for more than two seconds
before resetting the alarm.
Page 34
PRODUCT OVERVIEW
26 6SY Operation Manual
This Page Intentionally Left Blank
Page 35
6SY Operation Manual 27
BEFORE YOU
OPERATE
6SY Operation Manual
This section of the Operation Manual
describes the diesel fuel, engine oil, and
engine coolant specifications and how to
replenish them. It also describes the daily
engine checkout.
CAUTION
NEVER permit anyone to install
or operate the engine without
proper training.
• Read and understand this
Operation Manual before you
operate or service the engine
to ensure that you follow safe
operating practices and
maintenance procedures.
• Safety signs and labels are
additional reminders for safe
operating and maintenance
techniques.
• See your authorized Yanmar
marine dealer or distributor for
additional training.
0000002enMarine
Page 36
BEFORE YOU OPERATE
28 6SY Operation Manual
A DANGER
SCALD HAZARD!
• NEVER remove the coolant
filler cap if the engine is hot.
Steam and hot engine coolant
will escape and seriously burn
you. Allow the engine to cool
sufficiently before attempting
to remove the filler cap.
• Securely tighten the filler cap
after checking the coolant
level. Steam can escape during
engine operation if the cap is
loose.
• Failure to comply will result in
death or serious injury.
0000002enMarine
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Only fill the fuel tank with
diesel fuel. Filling the fuel tank
with gasoline may result in a
fire and will damage the
engine.
• NEVER refuel with the engine
running.
• Wipe up all spills immediately.
• Keep sparks, open flames or
any other form of ignition
(match, cigarette, static
electric source) well away
when refueling.
• NEVER overfill the fuel tank.
• Fill the fuel tank. Store any
containers containing fuel in a
well-ventilated area, away from
any combustibles or sources
of ignition.
• Failure to comply will result in
death or serious injury.
0000005en
Page 37
BEFORE YOU OPERATE
6SY Operation Manual 29
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is extremely
flammable and explosive under
certain conditions.
• Be sure to place the diesel fuel
container on the ground when
transferring the diesel fuel
from the pump to the
container. Hold the hose
nozzle firmly against the side
of the container while filling it.
This prevents static electricity
buildup which could cause
sparks and ignite fuel vapors.
• NEVER place diesel fuel or
other flammable material such
as oil, hay or dried grass close
to the engine during engine
operation or shortly after shut
down.
• Failure to comply will result in
death or serious injury.
0000014en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Before you operate the engine,
check for fuel leaks. Replace
rubberized fuel hoses every
two years or every 2000 hours
of engine operation, whichever
comes first, even if the engine
has been out of service.
Rubberized fuel lines tend to
dry out and become brittle
after two years or 2000 hours
of engine operation, whichever
comes first.
• Failure to comply will result in
death or serious injury.
0000015en
Page 38
BEFORE YOU OPERATE
30 6SY Operation Manual
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is extremely
flammable and explosive under
certain conditions.
• When you prime the fuel
system, operate the fuel
priming lever of the
mechanical fuel pump several
times until the fuel filter cup is
filled with fuel.
• NEVER open the air vent valve
while the fuel system is being
primed. The fuel filter has an
internal air bleed port.
• Failure to comply will result in
death or serious injury.
0000016en
A WARNING
HIGH PRESSURE
HAZARD!
• Avoid skin contact with high
pressure diesel fuel spray
caused by a fuel system leak
such as a broken fuel injection
line. High pressure fuel can
penetrate your skin and result
in serious injury. If you are
exposed to high pressure fuel
spray, obtain prompt medical
treatment.
• NEVER check for a fuel leak
with your hands. ALWAYS use
a piece of wood or cardboard.
Have your authorized Yanmar
marine dealer or distributor
repair the damage.
• Failure to comply could result
in death or serious injury.
0000008enMarine
Page 39
BEFORE YOU OPERATE
6SY Operation Manual 31
A WARNING
BURN HAZARD!
• If you must drain the engine oil
while it is still hot, stay clear of
the hot engine oil to avoid
being burned.
• ALWAYS wear eye protection.
• Failure to comply could result
in death or serious injury.
0000011en
A WARNING
BURN HAZARD!
• Keep your hands, and other
body parts, away from hot
engine surfaces such as the
muffler, exhaust pipe,
turbocharger (if equipped) and
engine block during operation
and shortly after you shut the
engine down. These surfaces
are extremely hot while the
engine is operating and could
seriously burn you.
• Failure to comply could result
in death or serious injury.
0000015en
A WARNING
BURN HAZARD!
• Wait until the engine cools
before you drain the engine
coolant. Hot engine coolant
may splash and burn you.
• Failure to comply could result
in death or serious injury.
0000016en
A CAUTION
COOLANT HAZARD!
• Wear eye protection and
rubber gloves when you
handle Long Life engine
coolant. If contact with the
eyes or skin should occur,
flush eyes and wash
immediately with clean water.
• Failure to comply may result in
minor or moderate injury.
0000005enMarine
Page 40
BEFORE YOU OPERATE
32 6SY Operation Manual
CAUTION
• Only use diesel fuels
recommended by Yanmar for
the best engine performance,
to prevent engine damage and
to comply with EPA warranty
requirements.
• Only use clean diesel fuel.
• NEVER remove primary
strainer from the fuel tank filler
port. If removed, dirt and
debris could get into the fuel
system causing it to clog.
0000004enMarine
CAUTION
• Only use the engine oil
specified. Other engine oils
may affect warranty coverage,
cause internal engine
components to seize, or
shorten engine life.
• Prevent dirt and debris from
contaminating engine oil.
Carefully clean the oil
cap / dipstick and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine oil. This may adversely
affect the lubricating
properties of the engine oil.
• NEVER overfill. Overfilling may
result in white exhaust smoke,
engine overspeed or internal
damage.
0000005en
CAUTION
• Only use the engine coolant
specified. Other engine
coolants may affect warranty
coverage, cause an internal
buildup of rust and scale
and / or shorten engine life.
• Prevent dirt and debris from
contaminating engine coolant.
Carefully clean the heat
exchanger cap and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine coolants. This may
adversely affect the properties
of the engine coolant.
0000006enTrans
Page 41
BEFORE YOU OPERATE
6SY Operation Manual 33
DIESEL FUEL
Diesel Fuel Specifications
Diesel fuel should comply with the
following specifications. The table lists
several worldwide specifications for diesel
fuels.
Additional Technical Fuel
Requirements
• The fuel cetane number should be equal
to 45 or higher.
• The sulfur content must not exceed 0.5%
by volume. Less than 0.05% is preferred.
• NEVER mix kerosene, used engine oil,
or residual fuels with the diesel fuel.
• Water and sediment in the fuel should
not exceed 0.05% by volume.
• Keep the fuel tank and fuel-handling
equipment clean at all times.
• Poor quality fuel can reduce engine
performance and / or cause engine
damage.
• Fuel additives are not recommended.
Some fuel additives may cause poor
engine performance. See your
authorized Yanmar marine dealer or
distributor for more information.
• Ash content not to exceed 0.01% by
volume.
• Carbon residue content not to exceed
0.35% by volume. Less than 0.1% is
preferred.
• Total aromatics content should not
exceed 35% by volume. Less than 30%
is preferred.
• PAH (polycyclic aromatic hydrocarbons)
content should be below 10% by volume.
DIESEL FUEL
SPECIFICATION
LOCATION
No. 2-D, No. 1-D,
ASTM D975-94
USA
EN590:96 European Union
ISO 8217 DMX International
BS 2869-A1 or A2 United Kingdom
JIS K2204 Grade No.2 Japan
Page 42
BEFORE YOU OPERATE
34 6SY Operation Manual
Diesel Fuel Lines
Install the lines between the fuel tank and
the fuel injection pump.
Be sure to install a drain cock
(Figure 1, (6)) at the bottom of the fuel
tank to remove water and contaminants.
Install an fuel filter / water separator
(Figure 1, (3)) and a fuel filter between the
fuel tank and the fuel injection pump.
Filling the Fuel Tank
0002050
1
4
5
7
8
9
10
2
3
6
Figure 1
1. Fuel Filter
2. Fuel Priming Pump
3. Fuel Filter / Water Separator
4. Fuel Return Line
5. Fuel Tank
6. Fuel Tank Drain Cock
7. Approximately 50 mm (1.96 in.)
8. Fuel Shutoff Valve
9. Less than 500 mm (19.68 in.)
10. To Fuel Injection Pump
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Only fill the fuel tank with
diesel fuel. Filling the fuel tank
with gasoline may result in a
fire and will damage the
engine.
• NEVER refuel with the engine
running.
• Wipe up all spills immediately.
• Keep sparks, open flames or
any other form of ignition
(match, cigarette, static
electric source) well away
when refueling.
• NEVER overfill the fuel tank.
• Fill the fuel tank. Store any
containers containing fuel in a
well-ventilated area, away from
any combustibles or sources
of ignition.
• Failure to comply will result in
death or serious injury.
0000005en
Page 43
BEFORE YOU OPERATE
6SY Operation Manual 35
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is extremely
flammable and explosive under
certain conditions.
• Be sure to place the diesel fuel
container on the ground when
transferring the diesel fuel
from the pump to the
container. Hold the hose
nozzle firmly against the side
of the container while filling it.
This prevents static electricity
buildup which could cause
sparks and ignite fuel vapors.
• NEVER place diesel fuel or
other flammable material such
as oil, hay or dried grass close
to the engine during engine
operation or shortly after shut
down.
• Failure to comply will result in
death or serious injury.
0000014en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Before you operate the engine,
check for fuel leaks. Replace
rubberized fuel hoses every
two years or every 2000 hours
of engine operation, whichever
comes first, even if the engine
has been out of service.
Rubberized fuel lines tend to
dry out and become brittle
after two years or 2000 hours
of engine operation, whichever
comes first.
• Failure to comply will result in
death or serious injury.
0000015en
CAUTION
• Only use diesel fuels
recommended by Yanmar for
the best engine performance,
to prevent engine damage and
to comply with EPA warranty
requirements.
• Only use clean diesel fuel.
• NEVER remove primary
strainer from the fuel tank filler
port. If removed, dirt and
debris could get into the fuel
system causing it to clog.
0000004enMarine
Page 44
BEFORE YOU OPERATE
36 6SY Operation Manual
To fill the fuel tank:
1. Clean the area around the fuel cap.
2. Remove the fuel cap from the fuel tank.
3. Stop fueling when the gauge shows the
fuel tank is full. NEVER overfill the fuel
tank.
4. Replace the fuel cap and hand-tighten.
Over-tightening the fuel cap will
damage it.
Bleeding the Fuel System
The fuel system needs to be bled under
the following conditions:
• Before starting the engine for the first
time.
• After running out of fuel and fuel has
been added to the fuel tank.
• After fuel system maintenance such as
changing the fuel filter and draining the
fuel filter / water separator, or replacing a
fuel system component.
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is extremely
flammable and explosive under
certain conditions.
• When you prime the fuel
system, operate the fuel
priming lever of the
mechanical fuel pump several
times until the fuel filter cup is
filled with fuel.
• NEVER open the air vent valve
while the fuel system is being
primed. The fuel filter has an
internal air bleed port.
• Failure to comply will result in
death or serious injury.
0000016en
CAUTION
• ALWAYS be environmentally
responsible.
• Follow the guidelines of the
EPA or other governmental
agencies for the proper
disposal of hazardous
materials such as engine oil,
diesel fuel and engine coolant.
Consult the local authorities or
reclamation facility.
• NEVER dispose of hazardous
materials irresponsibly by
dumping them into a sewer, on
the ground or into ground
water or waterways.
• Failure to follow these
procedures may seriously
harm the environment.
0000013en
Page 45
BEFORE YOU OPERATE
6SY Operation Manual 37
Figure 2
1. Install a transparent plastic hose on
each fuel rail bleeder valve
(Figure 2, (1)). Place the hoses in an
appropriate container.
2. Open the bleeder valve and operate
the hand pump (Figure 2, (2)) until
fuel flows without air bubbles. This
may take 130 - 150 pump strokes.
3. Close the bleeder valves and remove
the hoses.
4. Continue hand pumping until there is
resistance:
• Approximately 20 strokes after
replacing the fuel filter
• Approximately 50 strokes after
replacing a fuel injector
5. Start the engine and check for leaks.
If the engine fails to start after bleeding:
• Open the bleeder valves again and
operate the hand pump until fuel without
air bubbles flows out.
• Tighten the bleeder valves. Start the
engine and check for leaks.
ENGINE OIL
CAUTION
NEVER hold the key in the
START position for longer than
15 seconds or the starter motor
will overheat.
0000007en
CAUTION
• Only use the engine oil
specified. Other engine oils
may affect warranty coverage,
cause internal engine
components to seize, or
shorten engine life.
• Prevent dirt and debris from
contaminating engine oil.
Carefully clean the oil
cap / dipstick and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine oil. This may adversely
affect the lubricating
properties of the engine oil.
• NEVER overfill. Overfilling may
result in white exhaust smoke,
engine overspeed or internal
damage.
0000005en
Page 46
BEFORE YOU OPERATE
38 6SY Operation Manual
Engine Oil Specifications
Use an engine oil that meets or exceeds
the following guidelines and classifications:
Service Categories
• API Service Categories CD or higher
• ACEA Service Categories E-3, E-4, and
E-5
• JASO Service Category DH-1
Definitions
• API Classification (American Petroleum
Institute)
• ACEA Classification (Association des
Constructeurs Européens
d’Automobilies)
• JASO (Japanese Automobile Standards
Organization)
Notes:
1. Be sure the engine oil, engine oil
storage containers, and engine oil
filling equipment are free of
sediments and water.
2. Change the engine oil after the first
50 hours of operation and then at
every 250 hours thereafter.
3. Select the oil viscosity based on the
ambient temperature where the
engine is being operated. See the
SAE Service Grade Viscosity Chart
(Figure 3).
4. Yanmar does not recommend the
use of engine oil “additives.”
Additional Technical Engine Oil
Requirements:
The engine oil must be changed when the
Total Base Number (TBN) has been
reduced to 2.0. TBN (mgKOH/g) test
method; JIS K-201-5.2-2 (HCI),
ASTM D4739 (HCI).
Engine Oil Viscosity
Select the appropriate engine oil viscosity
based on the ambient temperature shown
in the SAE Service Grade Viscosity Chart
in (Figure 3).
SAE15W40 is the recommended oil
viscosity.
Figure 3
-4˚F 14˚F 32˚F 50˚F 68˚F 86˚F 104˚F
(-20˚C) (-10˚C) (0˚C) (10˚C) (20˚C) (30˚C) (40˚C)
SAE 10W
SAE 20W
SAE 10W-30
SAE 15W-40
SAE 20
SAE 30
SAE 40
0000005
Page 47
BEFORE YOU OPERATE
6SY Operation Manual 39
Maximum Angles of Inclination
During Operation
Maximum permissible angles during
operation vary, depending on the type of oil
sump (Figure 4).
Note: The specified angle may only
occur intermittently.
Figure 4
Checking Engine Oil
1. Make sure engine is level.
2. Remove dipstick (Figure 5, (1)) and
wipe with clean cloth.
3. Fully reinsert dipstick.
4. Remove dipstick. The oil level should
be between upper (Figure 5, (2)) and
lower (Figure 5, (3)) lines on the
dipstick.
5. Fully reinsert dipstick.
Figure 5
24°
26°
35° 35°
25°
25°
(2)
(3)
(1)
Page 48
BEFORE YOU OPERATE
40 6SY Operation Manual
Adding Engine Oil
1. Remove the oil fill port cap and fill with
engine oil.
2. Fill with oil to the upper limit
(Figure 5, (2)) on the dipstick
(Figure 5, (1)). Insert the dipstick fully
to check the level.
3. Tighten the fill port cap securely by
hand.
Selection of Marine Gear Oil
Refer to the instruction book for each
marine gear.
ENGINE COOLANT
CAUTION
• NEVER overfill the engine with
engine oil.
• ALWAYS keep the oil level
between upper and lower lines
on the oil cap / dipstick.
0000015en
A DANGER
SCALD HAZARD!
• NEVER remove the coolant
filler cap if the engine is hot.
Steam and hot engine coolant
will escape and seriously burn
you. Allow the engine to cool
sufficiently before attempting
to remove the filler cap.
• Securely tighten the filler cap
after checking the coolant
level. Steam can escape during
engine operation if the cap is
loose.
• Failure to comply will result in
death or serious injury.
0000002enMarine
Page 49
BEFORE YOU OPERATE
6SY Operation Manual 41
Engine Coolant Specifications
Use a Long Life Coolant (LLC) that meets
or exceeds the following guidelines and
specifications:
• ASTM D6210, D4985 (US)
• JIS K-2234 (Japan)
• SAE J814C, J1941, J1034 or J2036
(International)
Note: In the U.S., LLC is required for
the warranty to be valid.
Coolant (Closed Cooling System)
IMPORTANT
Always add LLC to soft
water - especially when operating
in cold weather. Without LLC,
cooling performance will decrease
due to scale and rust in the cooling
system. Water alone may freeze
and form ice; it expands
approximately 9% in volume.
Use the proper amount of coolant
concentrate for the ambient
temperature as specified by the
LLC manufacturer. LLC
concentration should be a
minimum of 30% to a maximum of
60%. Too much LLC will decrease
the cooling efficiency also.
Do not mix different types or
brands of LLC or a harmful sludge
may form.
Do not use hard water.
Water should be clean and free
from sludge or particles.
A CAUTION
COOLANT HAZARD!
• Wear eye protection and
rubber gloves when you
handle Long Life engine
coolant. If contact with the
eyes or skin should occur,
flush eyes and wash
immediately with clean water.
• Failure to comply may result in
minor or moderate injury.
0000005enMarine
CAUTION
• Only use the engine coolant
specified. Other engine
coolants may affect warranty
coverage, cause an internal
buildup of rust and scale
and / or shorten engine life.
• Prevent dirt and debris from
contaminating engine coolant.
Carefully clean the heat
exchanger cap and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine coolants. This may
adversely affect the properties
of the engine coolant.
0000006enTrans
Page 50
BEFORE YOU OPERATE
42 6SY Operation Manual
Following the manufacturer’s
recommendations. Use a proper LLC
which will not have any adverse effects on
the materials (cast iron, aluminum, copper,
etc.) of the engine’s fresh water cooling
system. See Engine Coolant
Specifications.
Replace engine coolant periodically,
according to the maintenance schedule in
this Operation Manual.
Remove scale from the cooling system
periodically by flushing the system.
Checking the Coolant Level
A DANGER
SCALD HAZARD!
• NEVER remove the coolant
filler cap if the engine is hot.
Steam and hot engine coolant
will escape and seriously burn
you. Allow the engine to cool
sufficiently before attempting
to remove the filler cap.
• Securely tighten the filler cap
after checking the coolant
level. Steam can escape during
engine operation if the cap is
loose.
• Failure to comply will result in
death or serious injury.
0000002enMarine
A WARNING
BURN HAZARD!
• Wait until the engine cools
before you drain the engine
coolant. Hot engine coolant
may splash and burn you.
• Failure to comply could result
in death or serious injury.
0000016en
Page 51
BEFORE YOU OPERATE
6SY Operation Manual 43
To Check the Coolant Level:
1. Open the coolant recovery tank fill cap
and check the coolant level.
• The correct level for a cold engine is
approximately 50 mm (2.0 in.) below
the full line.
2. Add coolant as necessary. Do not add
water.
A CAUTION
COOLANT HAZARD!
• Wear eye protection and
rubber gloves when you
handle Long Life engine
coolant. If contact with the
eyes or skin should occur,
flush eyes and wash
immediately with clean water.
• Failure to comply may result in
minor or moderate injury.
0000005enMarine
CAUTION
COOLANT HAZARD!
When adding large amounts of
coolant, NEVER pour cold
coolant into a hot engine.
The cylinder block and cylinder
head could crack.
00000029
CAUTION
• Only use the engine coolant
specified. Other engine
coolants may affect warranty
coverage, cause an internal
buildup of rust and scale
and / or shorten engine life.
• Prevent dirt and debris from
contaminating engine coolant.
Carefully clean the heat
exchanger cap and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine coolants. This may
adversely affect the properties
of the engine coolant.
0000006enTrans
Page 52
BEFORE YOU OPERATE
44 6SY Operation Manual
DAILY CHECKS
Before you head out for the day, make sure
the Yanmar engine is in good operating
condition. Make sure you check the
following items.
Visual Checks
1. Check for engine oil leaks.
2. Check for fuel leaks.
3. Check for engine coolant leaks.
4. Check for damaged or missing parts.
5. Check for loose, missing, or damaged
fasteners.
6. Check the electrical harnesses for
cracks, abrasions, and damaged or
corroded connectors.
7. Check hoses for cracks, abrasions, and
damaged, loose or corroded clamps.
8. Check the fuel filter / water separator
for presence of water and
contaminants. If you find any water or
contaminants, drain the fuel filter /
water separator. See Drain or Replace
the Fuel Filter / Water Separator on
page 91. If you have to drain the fuel
filter / water separator frequently, drain
the fuel tank and check for the
presence of water in your fuel supply.
See Drain the Fuel Tank on page 93.
A WARNING
HIGH PRESSURE
HAZARD!
• Avoid skin contact with high
pressure diesel fuel spray
caused by a fuel system leak
such as a broken fuel injection
line. High pressure fuel can
penetrate your skin and result
in serious injury. If you are
exposed to high pressure fuel
spray, obtain prompt medical
treatment.
• NEVER check for a fuel leak
with your hands. ALWAYS use
a piece of wood or cardboard.
Have your authorized Yanmar
marine dealer or distributor
repair the damage.
• Failure to comply could result
in death or serious injury.
0000008enMarine
CAUTION
It is important to perform daily
checks as listed in the Operation
Manual.
Periodic maintenance prevents
unexpected downtime, reduces
the number of accidents due to
poor engine performance and
helps extend the life of the
engine.
0000060enMarine
Page 53
BEFORE YOU OPERATE
6SY Operation Manual 45
Check Diesel Fuel, Engine Oil,
and Engine Coolant Levels
Follow the procedures in Filling the Fuel
Tank on page 34, Checking Engine Oil on
page 39 and Check Diesel Fuel, Engine
Oil, and Engine Coolant Levels on page 45
to check these levels.
Checking and Refilling Marine
Gear Oil
Refer to the operation manual for the
marine gear.
Checking the Battery Electrolyte
Level
Be sure to check the battery electrolyte
level before use. See Check the Battery
Electrolyte Level (Servicable Batteries
Only) on page 91.
Checking the Alternator Belt
Be sure to check the belt tension before
use. See Check and Adjust the Alternator
Belt on page 86.
Checking the Alarm Indicators
Check the instruments and alarm
indicators at regular intervals.
Preparing Fuel, Oil and Coolant
in Reserve
Prepare sufficient fuel for the day’s
operation. Always store engine oil and
coolant in reserve (for at least one refill) on
board, to be ready for emergencies.
CAUTION
If any problem is noted during
the visual check, the necessary
corrective action should be
taken before you operate the
engine.
0000021en
Page 54
BEFORE YOU OPERATE
46 6SY Operation Manual
This Page Intentionally Left Blank
Page 55
6SY Operation Manual 47
ENGINE
OPERATION
6SY Operation Manual
This section of the Operation Manual
describes the procedures for starting the
engine, checking engine performance
during operation, and shutting the engine
down.
CAUTION
NEVER permit anyone to install
or operate the engine without
proper training.
• Read and understand this
Operation Manual before you
operate or service the engine
to ensure that you follow safe
operating practices and
maintenance procedures.
• Safety signs and labels are
additional reminders for safe
operating and maintenance
techniques.
• See your authorized Yanmar
marine dealer or distributor for
additional training.
0000002enMarine
Page 56
ENGINE OPERATION
48 6SY Operation Manual
A DANGER
SCALD HAZARD!
• NEVER remove the coolant
filler cap if the engine is hot.
Steam and hot engine coolant
will escape and seriously burn
you. Allow the engine to cool
sufficiently before attempting
to remove the filler cap.
• Securely tighten the filler cap
after checking the coolant
level. Steam can escape during
engine operation if the cap is
loose.
• Failure to comply will result in
death or serious injury.
0000002enMarine
A DANGER
EXPLOSION HAZARD!
• Keep the area around the
battery well-ventilated. While
the engine is running or the
battery is charging, hydrogen
gas is produced which can be
easily ignited.
• Keep sparks, open flame and
any other form of ignition away
while the engine is running or
battery is charging.
• Failure to comply will result in
death or serious injury.
0000003en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Only use the key switch to start
the engine.
• NEVER jump start the engine.
Sparks caused by shorting the
battery to the starter terminals
may cause a fire or explosion.
• Failure to comply will result in
death or serious injury.
0000004en
Page 57
ENGINE OPERATION
6SY Operation Manual 49
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Only fill the fuel tank with
diesel fuel. Filling the fuel tank
with gasoline may result in a
fire and will damage the
engine.
• NEVER refuel with the engine
running.
• Wipe up all spills immediately.
• Keep sparks, open flames or
any other form of ignition
(match, cigarette, static
electric source) well away
when refueling.
• NEVER overfill the fuel tank.
• Fill the fuel tank. Store any
containers containing fuel in a
well-ventilated area, away from
any combustibles or sources
of ignition.
• Failure to comply will result in
death or serious injury.
0000005en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• NEVER remove the fuel cap
with the engine running.
• Failure to comply will result in
death or serious injury.
0000011en
Page 58
ENGINE OPERATION
50 6SY Operation Manual
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is extremely
flammable and explosive under
certain conditions.
• Be sure to place the diesel fuel
container on the ground when
transferring the diesel fuel
from the pump to the
container. Hold the hose
nozzle firmly against the side
of the container while filling it.
This prevents static electricity
buildup which could cause
sparks and ignite fuel vapors.
• NEVER place diesel fuel or
other flammable material such
as oil, hay or dried grass close
to the engine during engine
operation or shortly after shut
down.
• Failure to comply will result in
death or serious injury.
0000014en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Before you operate the engine,
check for fuel leaks. Replace
rubberized fuel hoses every
two years or every 2000 hours
of engine operation, whichever
comes first, even if the engine
has been out of service.
Rubberized fuel lines tend to
dry out and become brittle
after two years or 2000 hours
of engine operation, whichever
comes first.
• Failure to comply will result in
death or serious injury.
0000015en
A WARNING
SUDDEN MOVEMENT
HAZARD!
• Be sure the boat is in open
water away from other boats,
docks, and other obstructions
before increasing rpm.
• Failure to comply could result
in death or serious injury.
0000006enMarine
Page 59
ENGINE OPERATION
6SY Operation Manual 51
A WARNING
SEVER HAZARD!
• Keep hands and other body
parts away from
moving / rotating parts such as
the flywheel or PTO shaft.
• Wear tight fitting clothing and
keep your hair short or tie it
back while the engine is
running.
• Remove all jewelry before you
operate or service the engine.
• NEVER start the engine in
gear. Sudden movement of the
engine and / or vessel could
cause death or serious
personal injury.
• NEVER operate the engine
without the guards in place.
• Before you start the engine
make sure that all bystanders
are clear of the area.
• Keep children and pets away
while the engine is operating.
• Check before starting the
engine that any tools or shop
rags used during maintenance
have been removed from the
area.
• Failure to comply could result
in death or serious injury.
0000002enMarine
A WARNING
EXHAUST HAZARD!
• NEVER operate the engine in
an enclosed area such as a
garage, tunnel, underground
room, manhole or ship’s hold
without proper ventilation.
• NEVER block windows, vents,
or other means of ventilation if
the engine is operating in an
enclosed area. All internal
combustion engines create
carbon monoxide gas during
operation. Accumulation of
this gas within an enclosure
could cause illness or even
death.
• Make sure that all connections
are tightened to specifications
after repair is made to the
exhaust system.
• Failure to comply could result
in death or serious injury.
0000003en
Page 60
ENGINE OPERATION
52 6SY Operation Manual
A WARNING
ALCOHOL AND DRUG
HAZARD!
• NEVER operate the engine
while you are under the
influence of alcohol or drugs.
• NEVER operate the engine
when you are feeling ill.
• Failure to comply could result
in death or serious injury.
0000004en
A WARNING
EXPOSURE HAZARD!
• Wear personal protective
equipment such as gloves,
work shoes, eye and hearing
protection as required by the
task at hand.
• NEVER wear jewelry,
unbuttoned cuffs, ties or loose
fitting clothing when you are
working near moving / rotating
parts such as the cooling fan,
flywheel or PTO shaft.
• ALWAYS tie back long hair
when you are working near
moving / rotating parts such as
a cooling fan, flywheel, or PTO
shaft.
• NEVER operate the engine
while wearing a headset to
listen to music or radio
because it will be difficult to
hear the alert signals.
• Failure to comply could result
in death or serious injury.
0000005en
Page 61
ENGINE OPERATION
6SY Operation Manual 53
A WARNING
HIGH PRESSURE
HAZARD!
• Avoid skin contact with high
pressure diesel fuel spray
caused by a fuel system leak
such as a broken fuel injection
line. High pressure fuel can
penetrate your skin and result
in serious injury. If you are
exposed to high pressure fuel
spray, obtain prompt medical
treatment.
• NEVER check for a fuel leak
with your hands. ALWAYS use
a piece of wood or cardboard.
Have your authorized Yanmar
marine dealer or distributor
repair the damage.
• Failure to comply could result
in death or serious injury.
0000008enMarine
A WARNING
BURN HAZARD!
• If you must drain the engine oil
while it is still hot, stay clear of
the hot engine oil to avoid
being burned.
• ALWAYS wear eye protection.
• Failure to comply could result
in death or serious injury.
0000011en
A WARNING
BURN HAZARD!
• Keep your hands, and other
body parts, away from hot
engine surfaces such as the
muffler, exhaust pipe,
turbocharger (if equipped) and
engine block during operation
and shortly after you shut the
engine down. These surfaces
are extremely hot while the
engine is operating and could
seriously burn you.
• Failure to comply could result
in death or serious injury.
0000015en
Page 62
ENGINE OPERATION
54 6SY Operation Manual
A WARNING
BURN HAZARD!
• Wait until the engine cools
before draining seawater from
the cooling system. Hot
seawater may splash and burn
you.
• Failure to comply could result
in death or serious injury.
0000016enMarine
A CAUTION
COOLANT HAZARD!
• Wear eye protection and
rubber gloves when you
handle Long Life engine
coolant. If contact with the
eyes or skin should occur,
flush eyes and wash
immediately with clean water.
• Failure to comply may result in
minor or moderate injury.
0000005enMarine
CAUTION
Observe the following
environmental operating
conditions to maintain engine
performance and avoid
premature engine wear:
• Avoid operating in extremely
dusty conditions.
• Avoid operating in the
presence of chemical gases or
fumes.
0000003enMarine
CAUTION
• Only use diesel fuels
recommended by Yanmar for
the best engine performance,
to prevent engine damage and
to comply with EPA warranty
requirements.
• Only use clean diesel fuel.
• NEVER remove primary
strainer from the fuel tank filler
port. If removed, dirt and
debris could get into the fuel
system causing it to clog.
0000004enMarine
Page 63
ENGINE OPERATION
6SY Operation Manual 55
CAUTION
• Only use the engine oil
specified. Other engine oils
may affect warranty coverage,
cause internal engine
components to seize, or
shorten engine life.
• Prevent dirt and debris from
contaminating engine oil.
Carefully clean the oil
cap / dipstick and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine oil. This may adversely
affect the lubricating
properties of the engine oil.
• NEVER overfill. Overfilling may
result in white exhaust smoke,
engine overspeed or internal
damage.
0000005en
CAUTION
NEVER hold the key in the
START position for longer than
15 seconds or the starter motor
will overheat.
0000007en
CAUTION
NEVER use an engine starting
aid such as ether. Engine
damage will result.
0000009en
CAUTION
• Only use the engine coolant
specified. Other engine
coolants may affect warranty
coverage, cause an internal
buildup of rust and scale
and / or shorten engine life.
• Prevent dirt and debris from
contaminating engine coolant.
Carefully clean the heat
exchanger cap and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine coolants. This may
adversely affect the properties
of the engine coolant.
0000006enTrans
CAUTION
If any problem is noted during
the visual check, the necessary
corrective action should be
taken before you operate the
engine.
0000021en
CAUTION
If any indicator illuminates
during engine operation, stop
the engine immediately.
Determine the cause and repair
the problem before you continue
to operate the engine.
0000029en
Page 64
ENGINE OPERATION
56 6SY Operation Manual
CAUTION
Observe the following
environmental operating
conditions to maintain engine
performance and avoid
premature engine wear:
• NEVER run the engine if the
ambient temperature is above
+40°C (+104°F) or below -16°C
(+5°F)
◆ If the ambient temperature
exceeds +40°C (+104°F) the
engine may overheat and
cause the engine oil to break
down.
◆ If the ambient temperature
falls below -16°C (+5°F)
rubber components such as
gaskets and seals will
harden causing premature
engine wear and damage.
◆ See your authorized Yanmar
marine engine dealer or
distributor if the engine will
be operated in either
temperature extreme.
• See your authorized Yanmar
marine dealer or distributor if
you need to operate the engine
at high altitudes. At high
altitudes the engine will lose
power, run rough, and produce
exhaust gases that exceed the
design specifications.
0000065enMarine
CAUTION
Clean or replace the air cleaner
element if the air intake
restriction exceeds the value
listed in the Operation and
Service Manuals.
0000046enMarine
CAUTION
NEVER turn off the battery
switch (if equipped) or short the
battery cables during operation.
Damage to the electric system
will result.
0000061en
CAUTION
Be sure to close the seacock.
Neglecting to close the seacock
could allow water to leak into the
boat and may cause it to sink.
0000152en
Page 65
ENGINE OPERATION
6SY Operation Manual 57
STARTING ENGINE
To start the engine:
1. Open the seacock (if equipped).
2. Open the fuel tank cock.
3. Put transmission in neutral.
4. Turn the battery master switch (if
equipped) ON.
5. Press the ENG ON switch (if equipped)
or turn key switch ON.
Starting at Low Temperatures
Comply with local environmental
requirements. Use engine heaters to avoid
starting problems and white smoke.
To limit white smoke, run the engine at low
speed and under moderate load until the
engine reaches normal operating
temperature. A light load on a cold engine
provides better combustion and faster
engine warm-up than no load.
Avoid running the engine at idling speed
any longer than necessary.
SHUTTING DOWN THE
ENGINE
1. Check to see that there are no active
faults.
2. Push the OFF switch (if equipped) or
turn the key switch to OFF. Use the
emergency stop switch (if equipped)
only in an emergency.
3. Turn the battery master switch (if
equipped) OFF.
4. Close the fuel tank cock.
5. Close the seacock (if equipped).
CAUTION
NEVER hold the key in the
START position for longer than
15 seconds or the starter motor
will overheat.
0000007en
CAUTION
NEVER use an engine starting
aid such as ether. Engine
damage will result.
0000009en
CAUTION
For maximum engine life,
Yanmar recommends that when
shutting the engine down, you
allow the engine to run, without
load, for five minutes. This will
allow the engine components
that operate at high
temperatures, such as the
exhaust system, to cool slightly
before the engine itself is shut
down.
0000008enYDG
CAUTION
Be sure to close the seacock.
Neglecting to close the seacock
could allow water to leak into the
boat and may cause it to sink.
0000152en
Page 66
ENGINE OPERATION
58 6SY Operation Manual
CHECKING THE ENGINE
AFTER OPERATION
• Check that the key switch is in the OFF
position and battery master switch (if
equipped) is OFF.
• Fill the fuel tank. Make sure that the fill
cap and the area around the fill opening
are clean to avoid contamination of the
fuel.
• Turn off the inlet valve (seacock) for the
seawater system (if equipped).
• If there is a risk of freezing, check that
the closed coolant system contains
enough glycol. See Engine Coolant
Specifications on page 41.
• If there is a risk of freezing, empty the
seawater system.
• At temperatures below 0°C (32°F), drain
seawater system and connect the engine
heater (if equipped).
Page 67
6SY Operation Manual 59
PERIODIC
MAINTENANCE
6SY Operation Manual
This section of the Operation Manual
describes the procedures for proper care
and maintenance of the engine.
SAFETY PRECAUTIONS
Before You Operate
CAUTION
NEVER permit anyone to install
or operate the engine without
proper training.
• Read and understand this
Operation Manual before you
operate or service the engine
to ensure that you follow safe
operating practices and
maintenance procedures.
• Safety signs and labels are
additional reminders for safe
operating and maintenance
techniques.
• See your authorized Yanmar
marine dealer or distributor for
additional training.
0000002enMarine
Page 68
PERIODIC MAINTENANCE
60 6SY Operation Manual
During Operation and
Maintenance
A DANGER
EXPLOSION HAZARD!
• Keep the area around the
battery well-ventilated. While
the engine is running or the
battery is charging, hydrogen
gas is produced which can be
easily ignited.
• Keep sparks, open flame and
any other form of ignition away
while the engine is running or
battery is charging.
• Failure to comply will result in
death or serious injury.
0000003en
A DANGER
SCALD HAZARD!
• NEVER remove the coolant
filler cap if the engine is hot.
Steam and hot engine coolant
will escape and seriously burn
you. Allow the engine to cool
sufficiently before attempting
to remove the filler cap.
• Securely tighten the filler cap
after checking the coolant
level. Steam can escape during
engine operation if the cap is
loose.
• Failure to comply will result in
death or serious injury.
0000002enMarine
Page 69
PERIODIC MAINTENANCE
6SY Operation Manual 61
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• When you remove any fuel
system component to perform
maintenance (such as
changing the fuel filter) place
an approved container under
the opening to catch the fuel.
• NEVER use a shop rag to catch
the fuel. Vapors from the rag
are flammable and explosive.
• Wipe up any spills
immediately.
• Wear eye protection. The fuel
system is under pressure and
fuel could spray out when you
remove any fuel system
component.
• Failure to comply will result in
death or serious injury.
0000009en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• NEVER use diesel fuel as a
cleaning agent.
• Failure to comply will result in
death or serious injury.
0000012en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• NEVER remove the fuel cap
with the engine running.
• Failure to comply will result in
death or serious injury.
0000011en
Page 70
PERIODIC MAINTENANCE
62 6SY Operation Manual
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Only use the key switch to start
the engine.
• NEVER jump start the engine.
Sparks caused by shorting the
battery to the starter terminals
may cause a fire or explosion.
• Failure to comply will result in
death or serious injury.
0000004en
A DANGER
CRUSH HAZARD!
• When you need to transport an
engine for repair have a helper
assist you attach it to a hoist
and load it on a truck.
• NEVER stand under hoisted
engine. If the hoist mechanism
fails, the engine will fall on
you, causing serious injury or
death.
• Failure to comply will result in
death or serious injury.
0000008en
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Only fill the fuel tank with
diesel fuel. Filling the fuel tank
with gasoline may result in a
fire and will damage the
engine.
• NEVER refuel with the engine
running.
• Wipe up all spills immediately.
• Keep sparks, open flames or
any other form of ignition
(match, cigarette, static
electric source) well away
when refueling.
• NEVER overfill the fuel tank.
• Fill the fuel tank. Store any
containers containing fuel in a
well-ventilated area, away from
any combustibles or sources
of ignition.
• Failure to comply will result in
death or serious injury.
0000005en
Page 71
PERIODIC MAINTENANCE
6SY Operation Manual 63
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• Before you operate the engine,
check for fuel leaks. Replace
rubberized fuel hoses every
two years or every 2000 hours
of engine operation, whichever
comes first, even if the engine
has been out of service.
Rubberized fuel lines tend to
dry out and become brittle
after two years or 2000 hours
of engine operation, whichever
comes first.
• Failure to comply will result in
death or serious injury.
0000015en
A DANGER
EXPLOSION HAZARD!
• NEVER check the remaining
battery charge by shorting out
the terminals. This will result in
a spark and may cause an
explosion or fire. Use a
hydrometer to check the
remaining battery charge.
• If the electrolyte is frozen,
slowly warm the battery before
you recharge it.
• Failure to comply will result in
death or serious injury.
0000007en
Page 72
PERIODIC MAINTENANCE
64 6SY Operation Manual
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• If the unit has an electric fuel
pump, when you prime the fuel
system, turn the key switch to
the ON position for 10 to 15
seconds to allow the electric
fuel pump to prime the system.
• If the unit has a mechanical
fuel pump, when you prime the
fuel system, operate the fuel
priming lever of the
mechanical fuel pump several
times until the fuel filter cup is
filled with fuel.
• NEVER open the air vent valve
while the fuel system is being
primed. The fuel filter has an
internal air bleed port.
• Failure to comply will result in
death or serious injury.
0000010en
A DANGER
NEVER start the engine unless
the air filter is installed.
Failure to comply will result in
death or serious injury.
0000025en
A WARNING
SEVER HAZARD!
• Keep hands and other body
parts away from
moving / rotating parts such as
the flywheel or PTO shaft.
• Wear tight fitting clothing and
keep your hair short or tie it
back while the engine is
running.
• Remove all jewelry before you
operate or service the engine.
• NEVER start the engine in
gear. Sudden movement of the
engine and / or vessel could
cause death or serious
personal injury.
• NEVER operate the engine
without the guards in place.
• Before you start the engine
make sure that all bystanders
are clear of the area.
• Keep children and pets away
while the engine is operating.
• Check before starting the
engine that any tools or shop
rags used during maintenance
have been removed from the
area.
• Failure to comply could result
in death or serious injury.
0000002enMarine
Page 73
PERIODIC MAINTENANCE
6SY Operation Manual 65
A WARNING
EXHAUST HAZARD!
• NEVER operate the engine in
an enclosed area such as a
garage, tunnel, underground
room, manhole or ship’s hold
without proper ventilation.
• NEVER block windows, vents,
or other means of ventilation if
the engine is operating in an
enclosed area. All internal
combustion engines create
carbon monoxide gas during
operation. Accumulation of
this gas within an enclosure
could cause illness or even
death.
• Make sure that all connections
are tightened to specifications
after repair is made to the
exhaust system.
• Failure to comply could result
in death or serious injury.
0000003en
A WARNING
ALCOHOL AND DRUG
HAZARD!
• NEVER operate the engine
while you are under the
influence of alcohol or drugs.
• NEVER operate the engine
when you are feeling ill.
• Failure to comply could result
in death or serious injury.
0000004en
A WARNING
BURN HAZARD!
• Batteries contain sulfuric acid.
NEVER allow battery fluid to
come in contact with clothing,
skin or eyes. Severe burns
could result. ALWAYS wear
safety goggles and protective
clothing when servicing the
battery. If battery fluid contacts
the eyes and / or skin,
immediately flush the affected
area with a large amount of
clean water and obtain prompt
medical treatment.
• Failure to comply could result
in death or serious injury.
0000007en
Page 74
PERIODIC MAINTENANCE
66 6SY Operation Manual
A WARNING
EXPOSURE HAZARD!
• Wear personal protective
equipment such as gloves,
work shoes, eye and hearing
protection as required by the
task at hand.
• NEVER wear jewelry,
unbuttoned cuffs, ties or loose
fitting clothing when you are
working near moving / rotating
parts such as the cooling fan,
flywheel or PTO shaft.
• ALWAYS tie back long hair
when you are working near
moving / rotating parts such as
a cooling fan, flywheel, or PTO
shaft.
• NEVER operate the engine
while wearing a headset to
listen to music or radio
because it will be difficult to
hear the alert signals.
• Failure to comply could result
in death or serious injury.
0000005en
A WARNING
SUDDEN MOVEMENT
HAZARD!
• Be sure the boat is in open
water away from other boats,
docks, and other obstructions
before increasing rpm.
• Failure to comply could result
in death or serious injury.
0000006enMarine
A WARNING
HIGH PRESSURE
HAZARD!
• Avoid skin contact with high
pressure diesel fuel spray
caused by a fuel system leak
such as a broken fuel injection
line. High pressure fuel can
penetrate your skin and result
in serious injury. If you are
exposed to high pressure fuel
spray, obtain prompt medical
treatment.
• NEVER check for a fuel leak
with your hands. ALWAYS use
a piece of wood or cardboard.
Have your authorized Yanmar
marine dealer or distributor
repair the damage.
• Failure to comply could result
in death or serious injury.
0000008enMarine
Page 75
PERIODIC MAINTENANCE
6SY Operation Manual 67
A WARNING
SHOCK HAZARD!
• Turn off the battery switch (if
equipped) or disconnect the
negative battery cable before
servicing the electrical system.
• Check the electrical harnesses
for cracks, abrasions, and
damaged or corroded
connectors. ALWAYS keep the
connectors and terminals
clean.
• Failure to comply could result
in death or serious injury.
0000009en
A WARNING
ENTANGLEMENT
HAZARD!
• Stop the engine before you
begin to service it.
• NEVER leave the key in the key
switch when you are servicing
the engine. Someone may
accidentally start the engine
and not realize you are
servicing it. This could result
in a serious injury.
• If you must service the engine
while it is operating, remove all
jewelry, tie back long hair, and
keep your hands, other body
parts and clothing away from
moving / rotating parts.
• Failure to comply could result
in death or serious injury.
0000010en
A WARNING
BURN HAZARD!
• Wait until the engine cools
before you drain the engine
coolant. Hot engine coolant
may splash and burn you.
• Failure to comply could result
in death or serious injury.
0000016en
Page 76
PERIODIC MAINTENANCE
68 6SY Operation Manual
A WARNING
BURN HAZARD!
• If you must drain the engine oil
while it is still hot, stay clear of
the hot engine oil to avoid
being burned.
• ALWAYS wear eye protection.
• Failure to comply could result
in death or serious injury.
0000011en
A WARNING
BURN HAZARD!
• Wait until the engine cools
before draining seawater from
the cooling system. Hot
seawater may splash and burn
you.
• Failure to comply could result
in death or serious injury.
0000016enMarine
A WARNING
BURN HAZARD!
• Keep your hands, and other
body parts, away from hot
engine surfaces such as the
muffler, exhaust pipe,
turbocharger (if equipped) and
engine block during operation
and shortly after you shut the
engine down. These surfaces
are extremely hot while the
engine is operating and could
seriously burn you.
• Failure to comply could result
in death or serious injury.
0000015en
A WARNING
FIRE HAZARD!
• Undersized wiring systems can
cause an electrical fire.
• Failure to comply could result
in death or serious injury.
0000027en
Page 77
PERIODIC MAINTENANCE
6SY Operation Manual 69
A CAUTION
COOLANT HAZARD!
• Wear eye protection and
rubber gloves when you
handle Long Life engine
coolant. If contact with the
eyes or skin should occur,
flush eyes and wash
immediately with clean water.
• Failure to comply may result in
minor or moderate injury.
0000005enMarine
A CAUTION
FLYING OBJECT HAZARD!
• ALWAYS wear eye protection
when servicing engine and
when using compressed air or
high-pressure water. Dust,
flying debris, compressed air,
pressurized water or steam
may injure your eyes.
• Failure to comply may result in
minor or moderate injury.
0000003en
CAUTION
• Only use diesel fuels
recommended by Yanmar for
the best engine performance,
to prevent engine damage and
to comply with EPA warranty
requirements.
• Only use clean diesel fuel.
• NEVER remove primary
strainer from the fuel tank filler
port. If removed, dirt and
debris could get into the fuel
system causing it to clog.
0000004enMarine
CAUTION
NEVER attempt to adjust the low
or high idle speed limit screw.
This may impair the safety and
performance of the engine and
shorten its life. If adjustment is
ever required, see your
authorized Yanmar marine dealer
or distributor.
0000045enMarine
CAUTION
If any problem is noted during
the visual check, the necessary
corrective action should be
taken before you operate the
engine.
0000021en
Page 78
PERIODIC MAINTENANCE
70 6SY Operation Manual
CAUTION
Be sure to close the seacock.
Neglecting to close the seacock
could allow water to leak into the
boat and may cause it to sink.
0000152en
CAUTION
• If the vessel is equipped with a
water lift (water lock) muffler,
excessive cranking could
cause seawater to enter the
cylinders and damage the
engine. If the engine does not
start after cranking 15
seconds, close the thru-hull
water intake valve to avoid
filling the muffler with water.
Crank for 15 seconds or until
the engine starts. When the
engine does start, stop the
engine immediately and press
the switch to the OFF position.
• Be sure to re-open the seacock
and restart the engine. Operate
the engine normally.
0000151en
CAUTION
Observe the following
environmental operating
conditions to maintain engine
performance and avoid
premature engine wear:
• NEVER run the engine if the
ambient temperature is above
+40°C (+104°F) or below -16°C
(+5°F)
◆ If the ambient temperature
exceeds +40°C (+104°F) the
engine may overheat and
cause the engine oil to break
down.
◆ If the ambient temperature
falls below -16°C (+5°F)
rubber components such as
gaskets and seals will
harden causing premature
engine wear and damage.
◆ See your authorized Yanmar
marine engine dealer or
distributor if the engine will
be operated in either
temperature extreme.
• See your authorized Yanmar
marine dealer or distributor if
you need to operate the engine
at high altitudes. At high
altitudes the engine will lose
power, run rough, and produce
exhaust gases that exceed the
design specifications.
0000065enMarine
Page 79
PERIODIC MAINTENANCE
6SY Operation Manual 71
CAUTION
• Only use the engine coolant
specified. Other engine
coolants may affect warranty
coverage, cause an internal
buildup of rust and scale
and / or shorten engine life.
• Prevent dirt and debris from
contaminating engine coolant.
Carefully clean the heat
exchanger cap and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine coolants. This may
adversely affect the properties
of the engine coolant.
0000006enTrans
CAUTION
• Only use the engine oil
specified. Other engine oils
may affect warranty coverage,
cause internal engine
components to seize, or
shorten engine life.
• Prevent dirt and debris from
contaminating engine oil.
Carefully clean the oil
cap / dipstick and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine oil. This may adversely
affect the lubricating
properties of the engine oil.
• NEVER overfill. Overfilling may
result in white exhaust smoke,
engine overspeed or internal
damage.
0000005en
CAUTION
• NEVER overfill the engine with
engine oil.
• ALWAYS keep the oil level
between upper and lower lines
on the oil cap / dipstick.
0000015en
CAUTION
For maximum engine life,
Yanmar recommends that when
shutting the engine down, you
allow the engine to run, without
load, for five minutes. This will
allow the engine components
that operate at high
temperatures, such as the
exhaust system, to cool slightly
before the engine itself is shut
down.
0000008enYDG
CAUTION
NEVER use an engine starting
aid such as ether. Engine
damage will result.
0000009en
CAUTION
NEVER clean the coolant system
with caustic soda. The aluminum
parts may be damaged.
0000175en
Page 80
PERIODIC MAINTENANCE
72 6SY Operation Manual
CAUTION
Make sure the engine is installed
on a level surface. If a Yanmar
Marine Engine is installed at an
angle that exceeds the
specifications stated in the
Yanmar Marine Installation
manuals, engine oil may enter
the combustion chamber
causing excessive engine speed,
white exhaust smoke and
serious engine damage. This
applies to engines that run
continuously or those that run
for short periods of time.
0000010enMarine
CAUTION
New Engine Break In:
• On the initial engine start-up,
check for proper engine oil
pressure, diesel fuel leaks,
engine oil leaks, coolant leaks,
and for proper operation of the
indicators and / or gauges.
• During the first 50 hours of
operation operate your new
engine under a substantial
load at all times. For best
break-in results operate the
engine at various speeds.
• Operating the engine in
NEUTRAL must be avoided.
During the first 50 hours, avoid
operation below 2000 rpm.
• During the break-in period,
carefully observe the engine
oil pressure and engine
temperature.
• During the break-in period,
check the engine oil and
coolant levels frequently.
0000011enMarine
CAUTION
Be careful not to get any oil on
the belt(s). Oil on the belt causes
slipping and stretching. Replace
the belt if it is damaged.
0000153enMarine
Page 81
PERIODIC MAINTENANCE
6SY Operation Manual 73
CAUTION
If seawater is left inside of the
engine, it may freeze and
damage parts of the cooling
system when the ambient
temperature is below 0°C (32°F).
0000154en
CAUTION
NEVER allow engine oil or diesel
fuel oil to contact the flexible
rubber mount. Oil makes rubber
deteriorate.
0000155en
CAUTION
• ALWAYS be environmentally
responsible.
• Follow the guidelines of the
EPA or other governmental
agencies for the proper
disposal of hazardous
materials such as engine oil,
diesel fuel and engine coolant.
Consult the local authorities or
reclamation facility.
• NEVER dispose of hazardous
materials irresponsibly by
dumping them into a sewer, on
the ground or into ground
water or waterways.
• Failure to follow these
procedures may seriously
harm the environment.
0000013en
CAUTION
Protect the air cleaner,
turbocharger (if equipped) and
electric components from
damage when you use steam or
high-pressure water to clean the
engine.
0000014en
CAUTION
Establish a periodic
maintenance plan according to
the engine application and make
sure you perform the required
periodic maintenance at
intervals indicated. Failure to
follow these guidelines will
impair the engine’s safety and
performance characteristics,
shorten the engine’s life and may
affect the warranty coverage on
your engine.
0000024en
CAUTION
It is important to perform daily
checks as listed in the Operation
Manual.
Periodic maintenance prevents
unexpected downtime, reduces
the number of accidents due to
poor engine performance and
helps extend the life of the
engine.
0000060enMarine
Page 82
PERIODIC MAINTENANCE
74 6SY Operation Manual
PRECAUTIONS
The Importance of Periodic
Maintenance
Engine deterioration and wear occur in
proportion to the length of time the engine
has been in service and the conditions the
engine is subjected to during operation.
Periodic maintenance prevents
unexpected downtime, reduces the
number of accidents due to poor machine
performance and helps extend the life of
the engine.
CAUTION
If the fuel filter / water separator
is positioned higher than the fuel
level in the fuel tank, water may
not drip out when the fuel
filter / water separator drain cock
is opened. If this happens, turn
the air vent screw on the top of
the fuel filter / water separator
2-3 turns counterclockwise.
Be sure to tighten the air vent
screw after the water has drained
out.
0000025en
CAUTION
• When the engine is operated in
dusty conditions, clean the air
cleaner element more
frequently.
• NEVER operate the engine with
the air cleaner or element(s)
removed. This may allow
foreign material to enter the
engine and damage it.
0000026en
CAUTION
Clean or replace the air cleaner
element if the air intake
restriction exceeds the value
listed in the Operation and
Service Manuals.
0000046enMarine
CAUTION
NEVER turn off the battery
switch (if equipped) or short the
battery cables during operation.
Damage to the electric system
will result.
0000061en
Page 83
PERIODIC MAINTENANCE
6SY Operation Manual 75
Performing Periodic
Maintenance
Perform periodic maintenance procedures
in an open, level area free from traffic. If
possible, perform the procedures indoors
to prevent environmental conditions such
as rain, wind, or snow, from damaging the
engine.
The Importance of Daily Checks
Periodic Maintenance Schedules assume
that the daily checks are performed on a
regular basis. Make it a habit of performing
daily checks before the start of each
operating day. See Daily Checks on
page 44.
Keep a Log of Engine Hours and
Daily Checks
Keep a log of the number of hours the
engine is run each day and a log of the
daily checks performed. Also note the
date, type of repair (e.g., replaced
alternator), and parts used for any service
needed between the periodic maintenance
intervals. Periodic maintenance intervals
are every 50, 250, 500, 750, 1000 and
2000 engine hours. Failure to perform
periodic maintenance will shorten the life
of the engine.
Yanmar Replacement Parts
Yanmar recommends that you use genuine
Yanmar parts when replacement parts are
needed. Genuine replacement parts help
ensure long engine life.
Tools Required
Before you start any periodic maintenance
procedure make sure you have the tools
you need to perform all of the required
tasks.
Ask Your Authorized Yanmar
Marine Dealer or Distributor
For Help
Our professional service technicians have
the expertise and skills to help you with
any maintenance or service related
procedures.
A WARNING
EXHAUST HAZARD!
• NEVER operate the engine in
an enclosed area such as a
garage, tunnel, underground
room, manhole or ship’s hold
without proper ventilation.
• NEVER block windows, vents,
or other means of ventilation if
the engine is operating in an
enclosed area. All internal
combustion engines create
carbon monoxide gas during
operation. Accumulation of
this gas within an enclosure
could cause illness or even
death.
• Make sure that all connections
are tightened to specifications
after repair is made to the
exhaust system.
• Failure to comply could result
in death or serious injury.
0000003en
Page 84
PERIODIC MAINTENANCE
76 6SY Operation Manual
Required EPA Maintenance
USA Only
To maintain optimum engine performance
and compliance with the Environmental
Protection Agency (EPA) Regulations
Engines, it is essential that you follow the
Periodic Maintenance Schedule on
page 78 and Periodic Maintenance
Procedures which start on page 81.
EPA Requirements
USA Only
The following are the installation
requirements for the EPA. Unless these
requirements are met, the exhaust gas
emissions will not be within the limits
specified by the EPA.
Maximum exhaust gas restriction shall be
5.88 kPa; 600 mmAq (0.85 psi) or less.
Maximum air intake restriction shall be
6.23 kPa; 635 mmAq (0.90 psi) or less.
Clean or replace the air cleaner element if
the air intake restriction exceeds the above
mentioned value.
EPA REQUIREMENTS
The EPA emission regulation is applicable
only in USA.
Conditions to Ensure
Compliance with EPA
Emission Standards
This product is an EPA-approved engine.
The following are the conditions that must
be met in order to ensure that the
emissions during operation meet the EPA
standards. Be sure to follow these:
The operating conditions should be as
follows:
• Ambient temperature: -20° - 40°C
(-4° - 104°F)
• Relative humidity: 80% or lower
• Permissible value for intake negative
pressure: 3.9 kPa (400 mmAq) or lower
• Permissible value for exhaust back
pressure: 19.6 kPa (2000 mmAq) or
lower
The fuel and lubricating oil used should be
as follows:
• Diesel fuel oil: ASTM D975 No. 1-D or
No. 2-D, or equivalent (minimum of
cetane No. 45)
• Lubricating oil: Type API, Class CD
Be sure to perform inspections as outlined
in Periodic Maintenance Procedures on
page 81 and keep a record of the results.
Pay particular attention to these important
points:
• Replacing the engine oil
• Replacing the lube oil filter
• Replacing the fuel filter
• Cleaning the intake silencer (air cleaner)
Note: Inspections are divided into two
sections in accordance with who
is responsible for performing the
inspection: the user or the
maker.
Page 85
PERIODIC MAINTENANCE
6SY Operation Manual 77
Inspection and Maintenance
See Inspection and Maintenance of EPA
Emission-Related Parts on page 80 for the
EPA emission-related parts. Inspection
and maintenance procedures not shown in
the Inspection and Maintenance of EPA
Emission-Related Parts section are
covered in Periodic Maintenance
Schedule on page 78.
This maintenance must be performed to
keep the emission values of your engine in
the standard values during the warranty
period. The warranty period is determined
by the age of the engine or the number of
hours of operation.
Tightening Fasteners
Use the correct amount of torque when
you tighten fasteners on the machine.
Applying excessive torque may damage
the fastener or component and not enough
torque may cause a leak or component
failure.
Page 86
PERIODIC MAINTENANCE
78 6SY Operation Manual
PERIODIC MAINTENANCE
SCHEDULE
Daily and periodic maintenance is
important to keep the engine in good
operating condition. The following is a
summary of maintenance items by periodic
maintenance intervals. Periodic
maintenance intervals vary depending on
engine application, loads, diesel fuel and
engine oil used and are hard to establish
definitively. The following should be treated
only as a general guideline.
Engines with Low Operating
Hours
Run the engine until it reaches operating
temperature and then perform the
following maintenance procedures:
• Check the engine oil level. See Checking
Engine Oil on page 39.
• Check the coolant level. See Checking
the Coolant Level on page 42.
• Check the low pressure indicator. See
Checking the Alarm Indicators on
page 45.
• Check the fuel level. See Filling the Fuel
Tank on page 34.
• Checking the battery electrolyte level.
See Check the Battery Electrolyte Level
(Servicable Batteries Only) on page 91.
• Clean the battery. See Clean the
Battery on page 110.
• Check for any leakage, rectify as
necessary. See Check for Leakage of
Fuel, Engine Oil and Engine Coolant on
page 108.
CAUTION
Establish a periodic
maintenance plan according to
the engine application and make
sure you perform the required
periodic maintenance at
intervals indicated. Failure to
follow these guidelines will
impair the engine’s safety and
performance characteristics,
shorten the engine’s life and may
affect the warranty coverage on
your engine.
See your authorized Yanmar
marine dealer or distributor for
assistance when checking items
marked with a
z.
0000024en6LY3
Page 87
PERIODIC MAINTENANCE
6SY Operation Manual 79
c: Check : Replace z: Contact your authorized Yanmar marine dealer or distributor
System Item Daily
Periodic Maintenance Interval
Every
50 hrs. or
one month
whichever
comes
first
Every 250
hrs. or one
year
whichever
comes
first
Every 500
hrs. or 2
years
whichever
comes
first
Every 1000
hrs. or 4
years
whichever
comes
first
Every
2000 hrs.
or 8 years
whichever
comes
first
Whole Visual inspection of engine exterior c
Fuel System Check the fuel leve, and refill c
Drain the fuel tank c
Drain the fuel filter and the
fuel / water separator
c
Replace the fuel filter element
Check the unit injector rocker arms
z
1
(1st time)
z
1
Check the unit injector spray
pattern
z
1
(1st time)
z
1
Overhaul and check fuel feed
pump
z
Replace rubber fuel hoses Replace every 2 years or every 2000 hours, whichever comes first.
Lubricating
System
Check the engine oil
level
Crankcase c
Replace the engine oil Crankcase
(1st time)
Replace the engine oil filter
element
(1st time)
Clean engine oil cooler z
Cooling
System Seawater outlet
c
During
Operation
Check coolant level c
Check the seawater pump impeller c
Replace the engine coolant
Every year
When long life coolant is used, replace every two years. See Engine Coolant
Specifications on page 41.
Clean and check the seawater
passages
z
Clean seawater and engine cooling
system
z
Check or replace anodes
Air Intake and
Exhaust
System
Clean the air intake silencer c
Clean the exhaust/water mixing
elbow
c
Clean the turbocharger z
1
Flush charge air cooler z
Electrical
System
Check the alarm indicators c
Check the electrolyte level in the
battery
c
Adjust / replace the tension of the
alternator belt
c
(1st time)
c
Check the wiring connectors c
Engine
Cylinder Head
and Block
Check for leakage of fuel, engine
oil and engine coolant
c
After
starting
Tighten all major nuts and bolts z
Adjust intake / exhaust valve
clearance
z
(1st time)
z
Page 88
PERIODIC MAINTENANCE
80 6SY Operation Manual
1 Required to conform to U.S. EPA regulations. See EPA Requirements USA Only on page 76.
Note: These procedures are considered normal maintenance and are performed at
the owner’s expense.
Inspection and Maintenance of EPA Emission-Related Parts
Note: The inspection and maintenance items shown above to be performed at your
Yanmar dealer or distributor.
Miscellaneous
Items
Check the electronic control
system operation
c
c
(1st time)
Adjust the propeller shaft alignment
z
(1st time)
z
Check / replace flexible engine
mounts
c
Parts Interval
Clean fuel injection nozzle 1500 hours
Check fuel injection nozzle adjustment
3000 hours
Check fuel injection pump adjustment
Check turbocharger adjustment
Check electronic engine management system (EMS) and its associated
sensors and actuators
c: Check : Replace z: Contact your authorized Yanmar marine dealer or distributor
System Item Daily
Periodic Maintenance Interval
Every
50 hrs. or
one month
whichever
comes
first
Every 250
hrs. or one
year
whichever
comes
first
Every 500
hrs. or 2
years
whichever
comes
first
Every 1000
hrs. or 4
years
whichever
comes
first
Every
2000 hrs.
or 8 years
whichever
comes
first
Page 89
PERIODIC MAINTENANCE
6SY Operation Manual 81
PERIODIC MAINTENANCE
PROCEDURES
Perform the following maintenance after
the initial 50 hours of operation.
• Replace Engine Oil and Engine Oil Filter
• Clean Centrifugal Oil Cleaner
• Check and Adjust Alternator Belt
• Check Electronic Management System
(EMS) Operation
• Adjust Propeller Shaft Alignment
• Replace Crankcase Ventilation Filter
Replace Engine Oil and Engine
Oil Filter Element
The engine oil on a new engine becomes
contaminated from the initial break-in of
internal parts. It is very important that the
initial oil replacement is performed as
scheduled.
It is easiest and most effective to drain the
engine oil after operation while the engine
is still warm.
After Initial 50 Hours of
Operation
A WARNING
BURN HAZARD!
• If you must drain the engine oil
while it is still hot, stay clear of
the hot engine oil to avoid
being burned.
• ALWAYS wear eye protection.
• Failure to comply could result
in death or serious injury.
0000011en
CAUTION
• Only use the engine oil
specified. Other engine oils
may affect warranty coverage,
cause internal engine
components to seize, or
shorten engine life.
• Prevent dirt and debris from
contaminating engine oil.
Carefully clean the oil
cap / dipstick and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine oil. This may adversely
affect the lubricating
properties of the engine oil.
• NEVER overfill. Overfilling may
result in white exhaust smoke,
engine overspeed or internal
damage.
0000005en
Page 90
PERIODIC MAINTENANCE
82 6SY Operation Manual
To replace the engine oil and engine oil
filter element:
1. Remove the engine oil dipstick. Attach
the oil drain pump (if equipped) and
pump out the oil.
For easier draining, remove the engine
oil fill cap.
2. Turn the engine oil filter lid
(Figure 1, (1)) clockwise with a box
wrench to remove.
3. Lift out the filter housing lid
(Figure 1, (1)) with filter (Figure 1, (3)).
The filter housing will drain
automatically once the filter has been
removed.
Figure 1
4. Remove the filter
element(Figure 1, (3)) from the lid
(Figure 1, (1)) by carefully bending the
filter to one side.
5. Remove the O-ring (Figure 1, (2)) from
the lid (Figure 1, (1)).
6. Lubricate a new O-ring with clean
engine oil and install in the lid
(Figure 1, (1)).
7. Press a new filter element
(Figure 1, (3)) into the snap fastener in
the lid.
8. Make sure that all oil is drained from
the filter housing.
9. Replace the filter lid (Figure 1, (1)) and
tighten to 25 N·m (18 ft-lb).
Note: If the deposits in the centrifugal
cleaner are more than 20 mm
(3/4 in.) thick, replace the oil
filter more often. The same is
true for cleaning the centrifugal
oil cleaner and changing the oil.
See Clean the Centrifugal
Engine Oil Cleaner on page 83
10.Fill with new engine oil. See Adding
Engine Oil on page 40.
CAUTION
• ALWAYS be environmentally
responsible.
• Follow the guidelines of the
EPA or other governmental
agencies for the proper
disposal of hazardous
materials such as engine oil,
diesel fuel and engine coolant.
Consult the local authorities or
reclamation facility.
• NEVER dispose of hazardous
materials irresponsibly by
dumping them into a sewer, on
the ground or into ground
water or waterways.
• Failure to follow these
procedures may seriously
harm the environment.
0000013en
(4)
(3)
(2)
(1)
Page 91
PERIODIC MAINTENANCE
6SY Operation Manual 83
11.Perform a trial run and check for oil
leaks.
12.Approximately 10 minutes after
stopping the engine, remove the oil
dipstick and check the oil level. Add oil
if the level is too low.
Clean the Centrifugal Engine Oil
Cleaner
Clean the centrifugal engine oil cleaner
every time the oil is changed.
1. Clean the oil cleaner cover. Turn the nut
counterclockwise to remove. Carefully
remove the cover in case the oil is hot.
2. Lift out the rotor and turn the nut on the
rotor bowl counterclockwise three turns
(Figure 2).
Figure 2
• If the nut is jammed, clamp the nut in a
vise and turn the rotor three turns
counterclockwise by hand or with a
wrench (Figure 3).
IMPORTANT
NEVER clamp the rotor in a vise.
NEVER strike the rotor bowl.
Doing so may cause damage
resulting in imbalance.
Figure 3
CAUTION
• NEVER overfill the engine with
engine oil.
• ALWAYS keep the oil level
between upper and lower lines
on the oil cap / dipstick.
0000015en
A WARNING
BURN HAZARD!
• If you must drain the engine oil
while it is still hot, stay clear of
the hot engine oil to avoid
being burned.
• ALWAYS wear eye protection.
• Failure to comply could result
in death or serious injury.
0000011en
0002376
Page 92
PERIODIC MAINTENANCE
84 6SY Operation Manual
3. Grasp the rotor bowl and tap on the
rotor nut with your hand or a plastic
hammer to loosen the rotor from the
bowl.
4. Remove the strainer located on the
rotor (Figure 4). If the strainer is stuck,
use a screwdriver to carefully pry the
bottom edge until it comes loose from
the bottom plate.
Figure 4
5. Scrape off the deposits from the inside
of the rotor bowl (Figure 5).
• If there are no deposits, the cleaner is
not working properly.
• If the deposits are thicker than 20 mm
(3/4 in.), clean the oil cleaner more
often.
Figure 5
6. Wash all of the parts in suitable parts
cleaning solvent.
7. Make sure the nozzles on the rotor are
not blocked or damaged.
8. Make sure the bearings are not
damaged.
9. Inspect the O-ring in the rotor bowl for
damage and replace if necessary.
10.Install the O-ring in the rotor bowl
(Figure 6).
Figure 6
Page 93
PERIODIC MAINTENANCE
6SY Operation Manual 85
Reassemble the Rotor
1. Tighten the rotor nut firmly by hand
(Figure 7).
Figure 7
2. Make sure the shaft is not loose. If the
shaft is loose, see your authorized
Yanmar marine dealer or distributor.
3. Install the rotor. Turn the rotor by hand
to make sure that it rotates easily
(Figure 8).
Figure 8
4. Install the bowl and tighten the lock nut
to 15 N·m (133 in.-lb) (Figure 9, (1)).
Be careful not to damage the rotor
shaft, nut or bowl while tightening the
lock nut.
Figure 9
Functional Inspection
The rotor spins very fast and should
continue to turn when the engine has
stopped.
To check rotor rotation:
1. Stop the engine after it is warm.
2. Listen for a whirring sound from the
rotor or check if the cleaner housing is
vibrating.
• The rotor normally continues spinning
for 30 - 60 seconds after the engine
has stopped.
• If the rotor does not spin for 30 - 60
seconds after the engine has stopped,
disassemble it and inspect the parts
for damage.
(1)
Page 94
PERIODIC MAINTENANCE
86 6SY Operation Manual
Check and Adjust the
Alternator Belt
1. Check the belt by pushing on the
middle of the belt (Figure 10, (1)) with
your finger, exerting a force of
approximately 98 N, 10 kgf (22 lbf).
With proper tension, the belt should
deflect 8 - 10 mm (0.315 - 0.393 in.).
Figure 10
2. If the belt deflection is not to
specification, see your authorized
Yanmar dealer or distributor for belt
replacement.
Check Electronic Management
System (EMS) Operation
Check for fault codes. Refer to separate
manual provided by digital display
manufacturer.
Adjust Propeller Shaft
Alignment
Refer to reverse gear manufacturer
literature for alignment procedure.
A WARNING
ENTANGLEMENT
HAZARD!
• Stop the engine before you
begin to service it.
• NEVER leave the key in the key
switch when you are servicing
the engine. Someone may
accidentally start the engine
and not realize you are
servicing it. This could result
in a serious injury.
• If you must service the engine
while it is operating, remove all
jewelry, tie back long hair, and
keep your hands, other body
parts and clothing away from
moving / rotating parts.
• Failure to comply could result
in death or serious injury.
0000010en
CAUTION
Be careful not to get any oil on
the belt(s). Oil on the belt causes
slipping and stretching. Replace
the belt if it is damaged.
0000153enMarine
Page 95
PERIODIC MAINTENANCE
6SY Operation Manual 87
Replace the Closed Crankcase
Ventilation Filter Element
A WARNING
BURN HAZARD!
• If you must drain the engine oil
while it is still hot, stay clear of
the hot engine oil to avoid
being burned.
• ALWAYS wear eye protection.
• Failure to comply could result
in death or serious injury.
0000011en
CAUTION
• ALWAYS be environmentally
responsible.
• Follow the guidelines of the
EPA or other governmental
agencies for the proper
disposal of hazardous
materials such as engine oil,
diesel fuel and engine coolant.
Consult the local authorities or
reclamation facility.
• NEVER dispose of hazardous
materials irresponsibly by
dumping them into a sewer, on
the ground or into ground
water or waterways.
• Failure to follow these
procedures may seriously
harm the environment.
0000013en
Page 96
PERIODIC MAINTENANCE
88 6SY Operation Manual
1. Remove the drain line at the filter base.
2. Release the clamps (Figure 12, (2))
holding the filter container
(Figure 12, (1)) to the filter head.
3. Remove the filter container
(Figure 12, (1)) carefully, there may be
oil in the bottom of the container.
4. Remove the filter element.
5. Install a new O-ring at the base of the
head and check that there is an O-ring
on the top of the new filter.
6. Install the new filter into the center of
the filter head and press firmly.
Figure 11
7. Replace the container and lock the
clamps (Figure 12, (2)).
8. If the restriction indicator
(Figure 12, (3)) on the top of the filter is
red, remove the plastic cover and reset
the restriction indicator button.
9. Reinstall the drainage line.
Figure 12
CAUTION
• Only use the engine oil
specified. Other engine oils
may affect warranty coverage,
cause internal engine
components to seize, or
shorten engine life.
• Prevent dirt and debris from
contaminating engine oil.
Carefully clean the oil
cap / dipstick and the
surrounding area before you
remove the cap.
• NEVER mix different types of
engine oil. This may adversely
affect the lubricating
properties of the engine oil.
• NEVER overfill. Overfilling may
result in white exhaust smoke,
engine overspeed or internal
damage.
0000005en
(3)
(2)
(1)
Page 97
PERIODIC MAINTENANCE
6SY Operation Manual 89
After you complete the initial 50 hour
maintenance procedures, perform the
following procedures every 50 hours
thereafter.
• Drain Fuel Filter and Fuel Filter / Water
Separator
• Check Battery Electrolyte Level
Drain or Replace the Fuel Filter
Element and Fuel Filter / Water
Separator
Every 50 Hours of
Operation
A DANGER
FIRE AND EXPLOSION
HAZARD!
• Diesel fuel is flammable and
explosive under certain
conditions.
• When you remove any fuel
system component to perform
maintenance (such as
changing the fuel filter) place
an approved container under
the opening to catch the fuel.
• NEVER use a shop rag to catch
the fuel. Vapors from the rag
are flammable and explosive.
• Wipe up any spills
immediately.
• Wear eye protection. The fuel
system is under pressure and
fuel could spray out when you
remove any fuel system
component.
• Failure to comply will result in
death or serious injury.
0000009en
Page 98
PERIODIC MAINTENANCE
90 6SY Operation Manual
Drain or Replace the Fuel Filter Element
Figure 13
1. Close the fuel tank cock.
2. Loosen the drain plug. Drain off any
water or dirt.
3. Clean the outside of the filter and
remove it by turning it
counterclockwise.
4. Install a new filter and hand-tighten.
5. Drain the fuel filter / water separator.
See Drain or Replace the Fuel Filter /
Water Separator on page 91.
CAUTION
If the fuel filter / water separator
is positioned higher than the fuel
level in the fuel tank, water may
not drip out when the fuel
filter / water separator drain cock
is opened. If this happens, turn
the air vent screw on the top of
the fuel filter / water separator
2-3 turns counterclockwise.
Be sure to tighten the air vent
screw after the water has drained
out.
0000025en
CAUTION
• ALWAYS be environmentally
responsible.
• Follow the guidelines of the
EPA or other governmental
agencies for the proper
disposal of hazardous
materials such as engine oil,
diesel fuel and engine coolant.
Consult the local authorities or
reclamation facility.
• NEVER dispose of hazardous
materials irresponsibly by
dumping them into a sewer, on
the ground or into ground
water or waterways.
• Failure to follow these
procedures may seriously
harm the environment.
0000013en
Page 99
PERIODIC MAINTENANCE
6SY Operation Manual 91
Drain or Replace the Fuel Filter / Water
Separator
1. Make sure the fuel tank cock
(Figure 14, (1)) is closed.
Figure 14
2. Loosen the drain plug (Figure 14, (3))
at the bottom of the fuel filter / water
separator and drain off any water or
dirt.
3. Turn the filter container (Figure 14, (2))
counterclockwise to remove.
4. Remove the filter element.
5. Lubricate the seal and install a new
filter element into the container.
6. Install filter container and hand-tighten.
7. Open the fuel tank cock
(Figure 14, (1)).
8. After reinstalling the fuel filter and the
fuel filter / water separator, bleed air
from the fuel system. See Bleeding the
Fuel System on page 36.
Check the Battery Electrolyte
Level (Servicable Batteries
Only)
(3)
(2)
(1)
A WARNING
BURN HAZARD!
• Batteries contain sulfuric acid.
NEVER allow battery fluid to
come in contact with clothing,
skin or eyes. Severe burns
could result. ALWAYS wear
safety goggles and protective
clothing when servicing the
battery. If battery fluid contacts
the eyes and / or skin,
immediately flush the affected
area with a large amount of
clean water and obtain prompt
medical treatment.
• Failure to comply could result
in death or serious injury.
0000007en
CAUTION
NEVER turn off the battery
switch (if equipped) or short the
battery cables during operation.
Damage to the electric system
will result.
0000061en
Page 100
PERIODIC MAINTENANCE
92 6SY Operation Manual
Check the Battery Electrolyte Level
(Continued)
IMPORTANT
NEVER attempt to remove the covers or
fill a maintenance-free battery.
1. Do not operate with insufficient battery
electrolyte as the battery will be
destroyed.
2. Remove the plugs and check the
electrolyte level in all cells.
3. If the level is lower than the minimum fill
level (Figure 15, (1)), fill with distilled
water (Figure 15, (2)) (available in the
grocery store) up to the upper limit
(Figure 15, (3)) of the battery.
Figure 15
Note: The maximum fill level is
approximately 10 - 15 mm
(3/8-9/16 in.) above the plates.
Note: Battery fluid tends to evaporate
in high temperatures, especially
in summer. In such conditions,
inspect the battery earlier than
specified.
CAUTION
• ALWAYS be environmentally
responsible.
• Follow the guidelines of the
EPA or other governmental
agencies for the proper
disposal of hazardous
materials such as engine oil,
diesel fuel and engine coolant.
Consult the local authorities or
reclamation facility.
• NEVER dispose of hazardous
materials irresponsibly by
dumping them into a sewer, on
the ground or into ground
water or waterways.
• Failure to follow these
procedures may seriously
harm the environment.
0000013en
0002388
1
2
3
Loading...