service repair manual

1. SERVICE MANUAL
LIT-18616-03-08 6BJ-28197-1K-11
F300
LF300
F350
LF350

2. NOTICE
This manual has been prepared by Yamaha primarily for use by Yamaha dealers and their trained
mechanics when performing maintenance procedures and repairs to Yamaha equipment. It has
been written to suit the needs of persons who have the Bronze Technical Certificate of YTA (Yamaha
Technical Academy) marine or the equivalent basic understanding of the mechanical and electrical
concepts and procedures inherent in the work, for without such knowledge attempted repairs or ser-
vice to the equipment could render it unsafe or unfit for use.
Because Yamaha has a policy of continuously improving its products, models may differ in detail
from the descriptions and illustrations given in this publication. Use only the latest edition of this
manual. Authorized Yamaha dealers are notified periodically of modifications and significant
changes in specifications and procedures, and these are incorporated in successive editions of this
manual.
Important information
Particularly important information is distinguished in this manual by the following notations:
The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY IS
INVOLVED!
WARNING
Failure to follow WARNING instructions could result in severe injury or death to the machine
operator, a bystander, or a person inspecting or repairing the outboard motor.
CAUTION:
A CAUTION indicates special precautions that must be taken to avoid damage to the out-
board motor.
NOTE:
A NOTE provides key information to make procedures easier or clearer.
F300, LF300, F350, LF350
SERVICE MANUAL
©2007 by Yamaha Motor Corporation, U.S.A.
1st Edition, February 2008
All rights reserved.
Any reprinting or unauthorized use
without the written permission of
Yamaha Motor Corporation, U.S.A.
is expressly prohibited.
Printed in U.S.A.
LIT-18616-03-08

3. 0
1
2
3
4
5
General information
Specification
Technical features and description
Rigging information
Troubleshooting
Electrical system
6
7
8
9
Fuel system
Power unit
Lower unit
Bracket unit
GEN
INFO
SPEC
TECH
FEA
RIG
GING
ELEC
FUEL
POWR
LOWR
BRKT
TRBL
SHTG
Contents

4. 10
Maintenance
Index
Appendix
MNT
Contents

5. GEN
INFO
6BJ1K11
0
2
3
4
5
6
7
8
9
General information 0
Safety while working .....................................................................................0-1
Fire prevention ..........................................................................................0-1
Ventilation .................................................................................................0-1
Self-protection ..........................................................................................0-1
Part, lubricant, and sealant .......................................................................0-1
Special service tool ...................................................................................0-2
Tightening torque ......................................................................................0-2
Non-reusable part .....................................................................................0-2
Disassembly and assembly ......................................................................0-2
How to use this manual ................................................................................0-3
Manual format ...........................................................................................0-3
Symbol ......................................................................................................0-4
Abbreviation ..............................................................................................0-5
Model features ...............................................................................................0-7
General feature .........................................................................................0-7
Model designation ....................................................................................0-8
Serial number ...........................................................................................0-8
Special service tool ......................................................................................0-9

6. 0-1 6BJ1K11
GEN
INFO General information
Safety while working
To prevent an accident or injury and to
ensure quality service, follow the safety pro-
cedures provided below.
Fire prevention
Gasoline is highly flammable.
Keep gasoline and all flammable products
away from heat, sparks, and open flames.
Ventilation
Gasoline vapor and exhaust gas are heavier
than air and extremely poisonous. If inhaled
in large quantities they may cause loss of
consciousness and death within a short time.
When test running an engine indoors (e.g., in
a water tank) be sure to do so where ade-
quate ventilation can be maintained.
Self-protection
Protect your eyes by wearing safety glasses
or safety goggles during all operations involv-
ing drilling and grinding, or when using an air
compressor.
Protect your hands and feet by wearing pro-
tective gloves and safety shoes when neces-
sary.
Part, lubricant, and sealant
Use only genuine Yamaha parts, lubricants,
and sealants or those recommended by
Yamaha, when servicing or repairing the out-
board motor.
Under normal conditions, the lubricants men-
tioned in this manual should not harm or be
hazardous to your skin. However, you should
follow these precautions to minimize any risk
when working with lubricants.
1. Maintain good standards of personal and
industrial hygiene.
2. Change and wash clothing as soon as
possible if soiled with lubricants.
3. Avoid contact with skin. Do not, for exam-
ple, place a soiled rag in your pocket.
4. Wash hands and any other part of the
body thoroughly with soap and hot water
after contact with a lubricant or lubricant
soiled clothing has been made.
5. To protect your skin, apply a protective
cream to your hands before working on
the outboard motor.

7. 6BJ1K11 0-2
Safety while working
0
2
3
4
5
6
7
8
9
6. Keep a supply of clean, lint-free cloths for
wiping up spills, etc.
Special service tool
Use the recommended special service tools
to protect parts from damage. Use the right
tool in the right manner—do not improvise.
Tightening torque
Follow the tightening torque specifications
provided throughout the manual. When tight-
ening nuts, bolts, and screws, tighten the
large sizes first, and tighten fasteners starting
in the center and moving outward.
Non-reusable part
Always use new gaskets, seals, O-rings, cot-
ter pins, circlips, etc., when installing or
assembling parts.
Disassembly and assembly
1. Use compressed air to remove dust and
dirt during disassembly.
2. Apply engine oil to the contact surfaces
of moving parts before assembly.
3. Install bearings with the manufacture
identification mark in the direction indi-
cated in the installation procedure. In
addition, be sure to lubricate the bear-
ings liberally.
4. Apply a thin coat of water-resistant
grease to the lip and periphery of an oil
seal before installation.
5. Check that moving parts operate nor-
mally after assembly.

8. 0-3 6BJ1K11
GEN
INFO General information
How to use this manual
Manual format
The format of this manual has been designed to make service procedures clear and easy to under-
stand. Use the information below as a guide for effective and quality service.
• Parts are shown and detailed in an exploded diagram and are listed in the component list (see a
in the figure below for an example page).
• The component list consists of part names and quantities, as well as bolt and screw dimensions
(see b in the figure below).
• Symbols are used to indicate important aspects of a procedure, such as the grade of lubricant and
lubrication point (see c in the figure below).
• Tightening torque specifications are provided in the exploded diagrams (see d in the figure below
for an example), and in the related detailed instructions. Some torque specifications are listed in
stages as torque figures or angles in degrees.
• Separate procedures and illustrations are used to explain the details of removal, checking, and
installation where necessary (see e in the figure below for an example page).
NOTE:
For troubleshooting procedures, see Chapter 4, “Troubleshooting.”
5-11 6AW3K11
FUEL
Fuel system
Throttle body
No. Part name Q’ty Remarks
1 Plastic tie 1
2 Joint 1
3 Nut 4
4 Washer 2
5 Electronic throttle valve assembly 1
6 Gasket 1 Not reusable
7 Bolt 1 M6 20 mm
8 Washer 1
9 Intake air pressure sensor 1
10 Bolt 4 M8 18 mm
11 Crip 1
12 Plate 1
13 Gasket 1 Not reusable
14 Bolt 3 M6 20 mm
15 Bolt 6 M8 35 mm
16 Surge tank 1
17 Clamp 1
1
2
3
4
6
7
8
9
10
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
5
T
R
.
.
13 N m (1.3 kgf m, 9.6 ft Ib)
T
R
.
.
13 N m (1.3 kgf m, 9.6 ft Ib)
T
R
.
.
13 N m (1.3 kgf m, 9.6 ft Ib)
T
R
.
.
5 N m (0.5 kgf m, 3.7 ft Ib)
LT
242
LT
242
S6AW05038
6AW3K11 5-30
Vapor separator
1
2
3
4
5
5
7
8
9
5. Drain the fuel from the vapor separator
drain hose by pressing the pressure
check valve using a thin screwdriver.
WARNING
Reduce the fuel pressure before loosen-
ing the vapor separator drain screw, or
pressurized fuel will spray out and may
result in serious injury.
6. Tighten the drain screw.
Checking the vapor separator
1. Reduce the fuel pressure. See Chapter
5, “Reducing the fuel pressure.”
2. Check the needle valve. Replace needle
valve assembly if bent or worn.
3. Check the float. Replace the float if there
is deterioration.
4. Check the high-pressure fuel pump filter.
Clean the filter if there is dirt or residue.
5. Install the needle valve and float to the
vapor separator cover.
6. Place the vapor separator cover assem-
bly in the position shown in the illustra-
tion, and then measure the float height
a.
NOTE:
To measure the height of the float, it should
be resting on the needle valve. Do not press
the float.
T
R
.
.
Vapor separator drain screw:
2 N·m (0.2 kgf·m, 1.5 ft·lb)
a
b
S6AW05023
S6AL4350
Float height a:
60.5±3.0 mm (2.38±0.12 in)
a
S6AW05024
a
b
c
d
e

9. 6BJ1K11 0-4
How to use this manual
0
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3
4
5
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7
8
9
Symbol
The symbols below are designed to indicate the content of a chapter.
Symbols a to f indicate specific data.
a Special service tool
b Specified oil or fluid
c Specified engine speed
d Specified tightening torque
e Specified measurement
f Specified electrical value
(resistance, voltage, electric current)
Symbols g to m in an exploded diagram and text indicate the grade of lubricant and the lubrication
point.
g Apply Yamaha 4-stroke motor oil
h Apply gear oil
i Apply water resistant grease
(Yamaha grease A)
j Apply molybdenum disulfide grease
k Apply low temperature resistant grease
(Yamaha grease C)
l Apply corrosion resistant grease
(Yamaha grease D)
m Apply WR-No.2 grease
General information
GEN
INFO
Troubleshooting
TRBL
SHTG
Lower unit
LOWR
Specification
SPEC
Electrical system
ELEC
Bracket unit
BRKT
Technical features and
description
TECH
FEA
Fuel system
FUEL
Maintenance
MNT
Rigging information
RIG
GING
Power unit
POWR
a b c
T
R
.
.
d e f
g
E
h
G
i
A
j
M
k
C
l
D
m
1208B
WR-No.2

10. 0-5 6BJ1K11
GEN
INFO General information
Symbols n to w in an exploded diagram and text indicate the type of sealant or locking agent and
the application point.
n Apply ThreeBond 1208B
o Apply ThreeBond 1207D
p Apply ThreeBond 1322
q Apply ThreeBond 1386B
r Apply ThreeBond 1104J
s Apply LOCTITE 518 (red)
t Apply LOCTITE 271 (red)
u Apply LOCTITE 242 (blue)
v Apply LOCTITE 572 (white)
w Apply silicon sealant
Abbreviation
The following abbreviations are used in this service manual.
n
1208B
o
1207D
p
1322
q
1386B
r
1104J
s
518
LT
t
271
LT
u
242
LT
v
572
LT
w
SS
Abbreviation Description
ABYC American Boat and Yacht Council
AFT Aft end
API American Petroleum Institute
AWG American Wire Gauge
BOW Bow end
CA Crank Angle
CCA Cold Cranking Ampere
C/E Check Engine
DN Down side
ECM Electronic Control Module
ENG Engine
ETV Electronic Throttle Valve
EX Exhaust
EXH Exhaust
ID Identification
IDM Ionic current Detection Module
IN Intake
INT Intake
ION Ionic Current
ISC Idle Speed Control
LPS Lever Position Sensor
M.E.S. Multi Engine System
OCV Oil Control Valve
PCV Pressure Control Valve
PON Pump Octane Number = (RON + Motor Octane Number)/2
PORT Port side
PTT Power Trim and Tilt

11. 6BJ1K11 0-6
How to use this manual
0
2
3
4
5
6
7
8
9
RON Research Octane Number
R.C. Remote Control (Digital Electronic Control)
SAE Society of Automotive Engineers
SM Service Manual
SPS Shift Position Sensor
STBD Starboard side
STERN Stern side
TDC Top Dead Center
TPS Throttle Position Sensor
UP Upside
VCT Variable Camshaft Timing
W/F Water in Fuel
YDIS Yamaha Diagnostic System
Abbreviation Description

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13. 0-7 6BJ1K11
GEN
INFO General information
Model features
General feature
F300/LF300 and F350/LF350 OVERALL FEATURES;
• Electronic fuel injection, 60° V8, DOHC, 32-valves, VCT, 5,330 cm3
(325.2 cu. in) engine
• Use of common components between F150 and F350
• Electro deposition treatment for durability
• Easy startability and drivability
• Low noise and vibration
• Low emission in compliance with EPA 2008, CARB 3 STARS and EU1 regulations
• Digital Electronic Control system and Command Link Multifunction Meters for easy rigging and
precision control
A Power unit
• VCT (for intake valve)
• Flywheel installed with 6 bolts
• Crankshaft with drive sprocket
• Forged piston with molybdenum coating
• Crankcase cooler, fuel cooler
• Vapor gas treatment system
• Modularized fuel system components
• Dual exhaust passages and divided
exhaust manifold
• One piece top cowl with large water separa-
tor and roller locks
• Exclusive engine lifting eye
• Simple rigging grommet
B Electrical
• Electronic Fuel Injection (Multi-point and
Sequential injection)
• Digital Electronic Control and gauge sys-
tem
• New YDIS 1.30 version
• Tilt-up limiter settings by YDIS 1.30
• Sequential direct ignition
• Ionic current detection module for knock
control
• Water-cooled Rectifier Regulator and isola-
tor
• Water detection alert system
• Multi-engine system for alert mode and
auto engine speed synchronization
• Adjusting trolling speed function
C Bracket unit
• Large clamp bracket with 6 mounting holes.
• New PTT unit to deal with additional power
• Selectable 3 full tilt-up positions
D Upper case
• Dual idle silencers
• Oil pan capacity 8.0 L (8.45 US qt, 7.04 lmp
qt)
• Water-wall cooling system around muffler
E Lower unit
• Dual water inlets and large water pump
• Flat key for water pump impeller. Big drive
unit
• Large exclusive propeller (Saltwater series
XL)
• Reliable thrust receiver structure
• Drive shaft free play reduction structure
• Exhaust pressure reduction and prop
damper cooling system (same as F250)
A
B
C
D
E

14. 6BJ1K11 0-8
Model features
0
2
3
4
5
6
7
8
9
Model designation
Serial number
The outboard motor serial number is
stamped on a label attached to the port
clamp bracket.
a Model name
b Approved model code
c Transom height
d Serial number
a Model Description
F : 4-stroke regular rotation
LF: 4-stroke counter rotation
b Prop Shaft Horsepower
300: 300 HP
350: 350 HP
c Functions
T: Power trim and tilt
R: Remote control
d Transom Height
X: UL (25 in)
U: SUL (30 in)
F 350 T U R
b c d c
a
b
c
d
Model name
Approved
model code
Starting
serial No.
F300TR 6BJ 1000001–
LF300TR 6BK 1000001–
F350TR 6AW 1000001–
LF350TR 6AX 1000001–

15. 0-9 6BJ1K11
GEN
INFO General information
Special service tool
Engine lifting eye
90890-06820
Drilling plate
90890-06783
YDIS (CD-ROM, Ver. 1.30)
60V-WS853-04
YDIS (KIT)
60V-85300-04
Digital multimeter
YU-34899-A
Peak volt adapter
YU-39991
Test harness (6 pins)
YB-06872
Pressure/vacuum tester
YB-35956-A
Test harness (3 pins)
YB-06869
Test harness (3 pins)
YB-06870

16. 6BJ1K11 0-10
Special service tool
0
2
3
4
5
6
7
8
9
Spark checker
YM-34487
Test harness (4 pins)
YB-06878
Fuel pressure gauge adapter
YB-06842
Fuel pressure gauge
YB-06766
Compression gauge
YU-33223
Compression gauge extension
YB-06563
Flywheel holder
YB-06139
Balance hangar
90890-06822
Primary sheave holder
YS-01880-A
Valve guide remover
YB-06801