Yamaha 20D User manual

OWNER’S MANUAL
20D
25N
6L3-28199-78-E0

EMU25050
Read this owner’s manual carefully before operating your outboard motor.

Important manual information
EMU25101
To the owner
Thank you for choosing a Yamaha outboard
motor. This Owner’s Manual contains infor-
mation needed for proper operation, mainte-
nance and care. A thorough understanding
of these simple instructions will help you ob-
tain maximum enjoyment from your new
Yamaha. If you have any question about the
operation or maintenance of your outboard
motor, please consult a Yamaha dealer.
In this Owner’s Manual particularly important
information is distinguished in the following
ways.
The Safety Alert Symbol means AT-
TENTION! BECOME ALERT! YOUR SAFE-
TY IS INVOLVED!
WARNING
EWM00780
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 out-
board motor.
CAUTION:
ECM00700
A CAUTION indicates special precautions
that must be taken to avoid damage to the
outboard motor.
NOTE:
A NOTE provides key information to make
procedures easier or clearer.
Yamaha continually seeks advancements in
product design and quality. Therefore, while
this manual contains the most current prod-
uct information available at the time of print-
ing, there may be minor discrepancies
between your machine and this manual. If
there is any question concerning this manu-
al, please consult your Yamaha dealer.
To ensure long product life, Yamaha recom-
mends that you use the product and perform
the specified periodic inspections and main-
tenance by correctly following the instruc-
tions in the owner’s manual. Note that if you
do not follow these instructions, not only may
the product break down, but the warranty will
also be voided.
Some countries have laws or regulations re-
stricting users from taking the product out of
the country where it was purchased, and it
may be impossible to register the product in
the destination country. Additionally, the
warranty may not apply in certain regions.
When planning to take the product to another
country, consult the dealer where the prod-
uct was purchased for further information.
If the product was purchased used, please
consult your closest dealer for customer re-
registration, and to be eligible for the speci-
fied services.
NOTE:
The 20DMHO, 20DWO, 25NMHO and the
standard accessories are used as a base for
the explanations and illustrations in this
manual. Therefore some items may not ap-
ply to every model.
EMU25120
20D, 25N
OWNER’S MANUAL
©2005 by Yamaha Motor Co., Ltd.
1st Edition, March 2005
All rights reserved.
Any reprinting or unauthorized use
without the written permission of
Yamaha Motor Co., Ltd.
is expressly prohibited.
Printed in Japan

Table of contents
General information .......................... 1
Identification numbers record.......... 1
Outboard motor serial number .......... 1
Key number....................................... 1
EC label........................................... 1
Safety information ........................... 2
Important labels............................... 3
Warning labels .................................. 3
Fueling instructions ......................... 3
Gasoline............................................ 4
Engine oil .......................................... 4
Battery requirement......................... 4
Battery specifications ........................ 4
Without a rectifier or Rectifier
Regulator ........................................ 4
Propeller selection........................... 5
Start-in-gear protection ................... 5
Basic components ............................ 7
Main components............................ 7
Fuel tank ........................................... 7
Fuel joint ........................................... 8
Fuel gauge ........................................ 8
Fuel tank cap .................................... 8
Air vent screw ................................... 8
Remote control.................................. 8
Remote control lever......................... 8
Neutral interlock trigger..................... 9
Neutral throttle lever.......................... 9
Choke switch..................................... 9
Tiller handle ...................................... 9
Gear shift lever................................ 10
Throttle grip..................................... 10
Throttle indicator ............................. 10
Throttle friction adjuster................... 10
Engine stop lanyard switch ............. 11
Engine stop button .......................... 12
Choke knob for pull type ................. 12
Manual starter handle ..................... 12
Main switch ..................................... 12
Steering friction adjuster ................. 12
Trim tab with anode ........................ 13
Trim rod (tilt pin).............................. 13
Shallow water lever......................... 13
Tilt lock mechanism......................... 14
Tilt support bar ................................ 14
Top cowling lock lever(s) (turn
type) .............................................. 14
2-pin connector ............................... 14
Battery charging information ........... 15
Warning indicator ............................ 15
Warning system ............................ 15
Overheat warning ............................ 15
Oil level warning and oil filter
clogging warning ........................... 16
Operation ......................................... 18
Installation..................................... 18
Mounting the outboard motor .......... 18
Clamping the outboard motor..........19
Breaking in engine ........................ 20
Gasoline and engine oil mixing
chart (50:1).................................... 20
Procedure for oil injection models ... 20
Preoperation checks ..................... 21
Fuel ................................................. 21
Oil .................................................... 21
Controls ........................................... 21
Engine ............................................. 21
Operation after long period of
storage .......................................... 21
Filling fuel and engine oil .............. 22
Filling fuel for portable tank ............. 22
Filling oil for manual starter
model ............................................ 22
Oil level indicator operation............. 24
Operating engine .......................... 24
Feeding fuel (portable tank) ............ 24
Starting engine ................................ 25
Warming up engine....................... 30
Choke start models ......................... 30
Shifting.......................................... 30
Forward (tiller handle and remote
control models) ............................. 31
Reverse (manual tilt and hydro tilt
models) ......................................... 31
Stopping engine............................ 32
Procedure........................................ 32
Trimming outboard motor.............. 33
Adjusting trim angle for manual tilt
models .......................................... 33
Adjusting boat trim ..........................34

Table of contents
Tilting up and down ....................... 35
Procedure for tilting up.................... 35
Procedure for tilting down (manual
tilt models) .................................... 36
Cruising in shallow water .............. 36
Cruising in shallow water (manual
tilt models) .................................... 36
Cruising in other conditions........... 38
Maintenance..................................... 39
Specifications ................................ 39
Transporting and storing outboard
motor ........................................... 40
Clamp screw mounting models....... 40
Storing outboard motor ................... 41
Procedure ....................................... 41
Lubrication (oil injection models)..... 42
Battery care..................................... 42
Cleaning the outboard motor .......... 43
Checking painted surface of
motor............................................. 43
Periodic maintenance.................... 43
Replacement parts.......................... 43
Maintenance chart .......................... 44
Greasing ......................................... 46
Cleaning and adjusting spark
plug ............................................... 46
Checking fuel system...................... 47
Inspecting fuel filter ......................... 48
Cleaning fuel filter ........................... 48
Inspecting idling speed ................... 49
Checking water in engine oil tank ... 49
Checking wiring and connectors ..... 49
Exhaust leakage ............................. 49
Water leakage................................. 50
Checking propeller .......................... 50
Removing the propeller................... 51
Installing the Propeller .................... 51
Changing gear oil............................ 51
Cleaning fuel tank ........................... 52
Inspecting and replacing
anode(s)........................................ 53
Checking battery (for electric start
models) ......................................... 53
Connecting the battery.................... 54
Disconnecting the battery ............... 55
Checking top cowling ...................... 55
Coating the boat bottom.................. 55
Trouble Recovery............................ 56
Troubleshooting ............................ 56
Temporary action in emergency ... 59
Impact damage ............................... 59
Replacing fuse ................................ 59
Starter will not operate .................... 60
Emergency starting engine .............60
Treatment of submerged motor .... 62
Procedure........................................ 62