Yanmar 6SY Series User manual

6SY
series
OPERATION MANUAL
6SY Operation Manual
P/N 0A6301-G0000
MARINE
ENGINES

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.

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.

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:___________________________________________________________

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

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

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

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

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.
AThis 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.
ADANGER
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
AWARNING
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

SAFETY
26SY Operation Manual
SAFETY PRECAUTIONS
Before You Operate
ACAUTION
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

SAFETY
6SY Operation Manual 3
During Operation and
Maintenance
ADANGER
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
ADANGER
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

SAFETY
46SY Operation Manual
ADANGER
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
ADANGER
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
ADANGER
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

SAFETY
6SY Operation Manual 5
ADANGER
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
ADANGER
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

SAFETY
66SY Operation Manual
ADANGER
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
ADANGER
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

SAFETY
6SY Operation Manual 7
ADANGER
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
ADANGER
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

SAFETY
86SY Operation Manual
AWARNING
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
AWARNING
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

SAFETY
6SY Operation Manual 9
AWARNING
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
AWARNING
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

SAFETY
10 6SY Operation Manual
AWARNING
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
AWARNING
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
AWARNING
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

SAFETY
6SY Operation Manual 11
AWARNING
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
AWARNING
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

SAFETY
12 6SY Operation Manual
AWARNING
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
AWARNING
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
AWARNING
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
AWARNING
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