Yamaha C40 Manual

							 
Operation 
26 
cool.
4. Third through tenth hours:
Avoid operating at full throttle for more
than 5 minutes at a time. Let the engine
cool between full-throttle runs. Vary en-
gine speed occasionally.
5. After the first 10 hours:
Operate the engine normally. Use only
straight gasoline in the fuel tank. The
Yamaha oil injection system provides
proper lubrication for normal operation. 
EMU27102 
Preoperation checks
WARNING
 
EWM00080  
If any item in the preoperation check is
not working properly, have it inspected
and repaired before operating the out-
board motor. Otherwise an accident 
could occur.
CAUTION:
 
ECM00120  
Do not start the engine out of water. Over-
heating and serious engine damage can 
occur. 
EMU27111 
Fuel 
 
Check to be sure you have plenty of fuel
for your trip. 
 
Make sure there are no fuel leaks or gaso-
line fumes. 
 
Check fuel line connections to be sure they
are tight (if equipped Yamaha fuel tank or
boat tank). 
 
Be sure the fuel tank is positioned on a se-
cure, flat surface, and that the fuel line is
not twisted or flattened, or likely to contact
sharp objects (if equipped Yamaha fuel
tank or boat tank). 
EMU27120 
Oil 
 
Check to be sure you have plenty of oil for
your trip. 
EMU27130 
Controls 
 
Check throttle, shift, and steering for prop-
er operation before starting the engine. 
 
The controls should work smoothly, with-
out binding or unusual free play. 
 
Look for loose or damaged connections. 
 
Check operation of the starter and stop
switches when the outboard motor is in the
water. 
EMU27140 
Engine 
 
Check the engine and engine mounting. 
 
Look for loose or damaged fasteners. 
 
Check the propeller for damage. 
EMU27170 
Operation after a long period of 
storage 
When operating the engine after a long peri-
od (12 months) of storage, proceed as fol-
lows:
1. Use a 50:1 gasoline-oil mixture to start
the engine.
2. Start the engine. Leave it idling.
WARNING
 
EWM00090  
 
Do not touch or remove electrical parts
when starting or during operation. 
 
Keep hands, hair, and clothes away
from the flywheel and other rotating 
parts while the engine is running. 
3. Watch for oil flowing through the oil feed
pipes. After any air in the oil lines has
been expelled, the oil injection system
should supply oil normally. If no oil is
flowing after 10 minutes of idling, consult
your Yamaha dealer.✩✦✯✬✤✲✲✣ ✥✩ 	
 


 
						

							 
Operation 
27
CAUTION:
 
ECM00130  
Be sure to take the above steps when op-
erating the engine after a long period of
storage. Otherwise engine seizure could 
occur. 
EMU27233 
Filling fuel and engine oil 
EMU27242 
Filling fuel for portable tank
WARNING
 
EWM00060  
Gasoline and its vapors are highly flam-
mable and explosive. Keep away from
sparks, cigarettes, flames, or other 
sources of ignition. 
1. Remove the fuel tank cap.
2. Fill the fuel tank carefully.
3. Close the cap securely after refueling.
Wipe up any spilled fuel. 
EMU27270 
Ring Free Fuel Additive 
Gasoline is a precise blend of many different
substances, each chosen to give certain
characteristics. Gasoline blends have been
changing in recent years in response to con-
cerns about pollution and resulting emis-
sions regulations. One of the most obvious
changes has been the elimination of lead
from most fuels.
As gasoline has changed, the amount of ad-
ditives such as aromatics and oxygenates
has increased. These additives are impor-
tant for the engines in passenger cars, but
they can have detrimental effects in marine
engines, because of increased deposits in
the combustion chamber. When enough de-
posits collect, piston rings begin sticking.
Performance drops and engine wear in-
creases dramatically.
While many additives available may reduce
deposits, Yamaha recommends the use of 
Ring Free Fuel Additive 
, available from
your Yamaha dealer.  
Ring Free Fuel Addi-
tive 
 has repeatedly proven its ability to clean
combustion deposits from inside the engine,
notably the critical piston-ring-land area, and
fuel system components. Follow product la-
beling for use instructions. Fuel tank capacity (if equipped Yamaha 
fuel tank):
25 L (6.60 US gal) (5.50 Imp.gal)
ZMU03367ZMU03012
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Operation 
28 
EMU27311 
Filling oil for electric start models
WARNING
 
EWM00530  
Do not add gasoline into the oil tank. Fire 
or explosion could result. 
This engine uses the Yamaha oil injection
system, which provides superior lubrication
by ensuring the proper oil ratio for all operat-
ing conditions. No fuel premixing is needed.
Simply pour gasoline into the fuel tank and
oil into the oil tank. Convenient indicator seg-
ments indicate the status of the oil supply.
For details on reading the indicator seg-
ments, see page 29.
To fill the engine oil tank, proceed as follows:
1. Turn the oil filler access cap on the top
cowling counterclockwise and open it.
2. Open the oil tank filler cap by pulling the
tab on the cap.3. Slowly pour the engine oil into the en-
gine oil tank.
4. After filling, replace the all caps secure-
ly. Engine oil tank capacity:
1.5 L (1.59 US qt) (1.32 Imp.qt)
ZMU03369
 
1. Oil filler access cap
2. Oil tank filler cap
ZMU03370
ZMU03371
2
1
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Operation 
29 
EMU27321 
Oil level indicator operation 
The various functions of the oil level system are as follows: 
EMU27350 
Electric start models 
EMU27450 
Operating engine 
EMU27461 
Feeding fuel (portable tank)
WARNING
 
EWM00420  
 
Before starting the engine, make sure
that the boat is tightly moored and that
you can steer clear of any obstructions.
Be sure there are no swimmers in the
water near you. 
 
When the air vent screw is loosened,
gasoline vapor will be released. Gaso-
line is highly flammable, and its vaporsare flammable and explosive. Refrain
from smoking, and keep away from
open flames and sparks while loosen-
ing the air vent screw. 
 
This product emits exhaust gases
which contain carbon monoxide, a col-
orless, odorless gas which could cause
brain damage or death when inhaled.
Symptoms include nausea, dizziness,
and drowsiness. Keep cockpit and cab-
in areas well ventilated. Avoid blocking 
exhaust outlets. 
1. If there is an air vent screw on the fuel 
Oil level 
warning 
indicator 
(digital 
tachometer)Oil level 
warning 
indicator 
(analog 
tachometer/
bottom 
cowling)Engine oil tank Remarks 
Green
more than 450 
cm 
3
 
 (0.48 US qt, 
0.40 Imp qt)No refilling necessary.
Yellow
from 450 cm 
3
 
 
(0.48 US qt, 0.40 
Imp qt) down to 
200 cm 
3
 
 (0.21 US 
qt, 0.18 Imp qt)Add oil; see page 28.
Red
200 cm 
3
 
 (0.21 US 
qt, 0.18 Imp qt) or 
less 
 
Buzzer sounds in 
remote control box 
and engine speed is 
limited to about 2000 
r/min to help con-
serve oil. 
 
Check oil filter for 
clogging.✩✦✯✬✤✲✲✣ ✥✬ 	
 


 
						

							 
Operation 
30 
tank cap, loosen it 2 or 3 turns.
2. If there is a fuel joint on the motor, firmly
connect the fuel line to the joint. Then
firmly connect the other end of the fuel
line to the joint on the fuel tank.
3. If a steering friction adjuster is provided
on your outboard motor, securely attach
the fuel line to the fuel line clamp.
NOTE:
 
During engine operation place the tank hori-zontally, otherwise fuel cannot be drawn 
from the fuel tank.
4. Squeeze the primer pump with the outlet
end up until you feel it become firm. 
EMU27490 
Starting engine 
EMU27592 
Electric start / prime start models 
1. Place the gear shift lever in neutral.
NOTE:
 
The start-in-gear protection device prevents
the engine from starting except when in neu- 
tral.
2. Attach the engine stop switch lanyard to
a secure place on your clothing, or your
arm or leg. Then install the lock plate on
the other end of the lanyard into the en-
ZMU02295
ZMU03100
ZMU02024
ZMU02025
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Operation 
31 
gine stop switch.
WARNING
 
EWM00120  
 
Attach the engine stop switch lanyard
to a secure place on your clothing, or
your arm or leg while operating. 
 
Do not attach the lanyard to clothing
that could tear loose. Do not route the
lanyard where it could become entan-
gled, preventing it from functioning. 
 
Avoid accidentally pulling the lanyard
during normal operation. Loss of en-
gine power means the loss of most
steering control. Also, without engine
power, the boat could slow rapidly. This
could cause people and objects in the 
boat to be thrown forward. 
3. Place the throttle grip in the “”
(start) position. After the engine starts,
return the throttle to the fully closed po-
sition.4. Turn the main switch to “” (start),
and hold it for a maximum of 5 seconds.
5. Immediately after the engine starts, re-
lease the main switch and allow it to re-
turn to “” (on).
CAUTION:
 
ECM00191  
 
Never turn the main switch to “”
(start) while the engine is running. 
 
Do not keep the starter motor turning
for more than 5 seconds. If the starter
motor is turned continuously for more
than 5 seconds, the battery will be
quickly discharged, thus making it im-
possible to start the engine. The starter
can also be damaged. If the engine will
not start after 5 seconds of cranking,
return the main switch to “” (on), wait
10 seconds, then crank the engine 
again.
NOTE:
 
 
When the engine is cold, it needs to be
warmed up. For further information, see
page 33. 
 
If the engine is warm and fails to start,
open the throttle slightly and try to start the
engine again. If the engine still fails to 
start, see page 60.✩✦✯✬✤✲✲✣ ✦✤ 	
 


 
						

							 
Operation 
32 
EMU27662 
Electric start and remote control models 
1. Place the remote control lever in neutral.
NOTE:
 
The start-in-gear protection device prevents
the engine from starting except when in neu- 
tral.
2. Attach the engine stop switch lanyard to
a secure place on your clothing, or your
arm or leg. Then install the lock plate on
the other end of the lanyard into the en-
gine stop switch.
WARNING
 
EWM00120  
 
Attach the engine stop switch lanyard
to a secure place on your clothing, or
your arm or leg while operating. 
 
Do not attach the lanyard to clothing
that could tear loose. Do not route the
lanyard where it could become entan-
gled, preventing it from functioning. 
 
Avoid accidentally pulling the lanyard
during normal operation. Loss of en-
gine power means the loss of most
steering control. Also, without engine
power, the boat could slow rapidly. This
could cause people and objects in the 
boat to be thrown forward. 
3. Turn the main switch to “” (on).
4. Turn the main switch to “” (start),
and hold it for a maximum of 5 seconds.
5. Immediately after the engine starts, re-
lease the main switch and allow it to re-
turn to “” (on).
CAUTION:
 
ECM00191  
 
Never turn the main switch to “”
(start) while the engine is running. 
 
Do not keep the starter motor turning
for more than 5 seconds. If the starter
motor is turned continuously for more
than 5 seconds, the battery will be
quickly discharged, thus making it im-
possible to start the engine. The starter
can also be damaged. If the engine will
not start after 5 seconds of cranking,
return the main switch to “” (on), wait
10 seconds, then crank the engine✩✦✯✬✤✲✲✣ ✦✥ 	
 


 
						

							 
Operation 
33 
again.
NOTE:
 
 
When the engine is cold, it needs to be
warmed up. For further information, see
page 33. 
 
If the engine is warm and fails to start,
open the throttle slightly and try to start the
engine again. If the engine still fails to 
start, see page 60. 
EMU27670 
Warming up engine 
EMU27702 
Electric start and prime start models 
1. After starting the engine, allow it to idle
for 3 minutes to warm up. Failure to do
so will shorten engine life.
2. Check for a steady flow of water from the
cooling water pilot hole.
CAUTION:
 
ECM00511  
A continuous flow of water from the cool-
ing water pilot hole shows that the water
pump is pumping water through the cool-
ing passages. If water is not flowing out
of the hole at all times while the engine is
running, overheating and serious dam-
age could occur. Stop the engine and
check whether the cooling water inlet on
the lower case or the cooling water pilot
hole is blocked. Consult your Yamaha
dealer if the problem cannot be located 
and corrected. 
EMU27740 
Shifting
WARNING
 
EWM00180  
Before shifting, make sure there are no
swimmers or obstacles in the water near 
you.
CAUTION:
 
ECM00220  
To change the boat direction or shifting
position from forward to reverse or vice-
versa, first close the throttle so that the 
engine idles (or runs at low speeds). 
EMU27763 
Forward (tiller handle and remote 
control models) 
Tiller control models
1. Place the throttle grip in the fully closed
position.
2. Move the gear shift lever quickly and
ZMU03391
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Operation 
34 
firmly from neutral to forward.
Remote control models
1. Pull up the neutral interlock trigger (if
equipped) and move the remote control
lever quickly and firmly from neutral to
forward.
 
EMU27784 
Reverse (automatic reverse lock and 
power trim and tilt models)
WARNING
 
EWM00190  
When operating in reverse, go slowly. Do
not open the throttle more than half. Oth-
erwise the boat could become unstable,
which could result in loss of control and 
an accident. 
Tiller control models
1. Place the throttle grip in the fully closed
position.2. Move the gear shift lever quickly and
firmly from neutral to reverse.
Remote control models
1. Pull up the neutral interlock trigger (if
equipped) and move the remote control
lever quickly and firmly from neutral to
reverse.
 
EMU27820 
Stopping engine 
Before stopping the engine, first let it cool off
for a few minutes at idle or low speed. Stop-✩✦✯✬✤✲✲✣ ✦✧ 	
 


 
						

							 
Operation 
35 
ping the engine immediately after operating
at high speed is not recommended. 
EMU27844 
Procedure 
1. Push and hold the engine stop button or
turn the main switch to “” (off).
2. After stopping the engine, disconnect
the fuel line if there is a fuel joint on the
outboard motor.
3. Tighten the air vent screw on the fuel
tank cap (if equipped).4. Remove the key if the boat will be left
unattended.
NOTE:
 
The engine can also be stopped by pulling
the lanyard and removing the lock plate from
the engine stop switch, then turning the main 
switch to “” (off). 
EMU27861 
Trimming outboard motor 
The trim angle of the outboard motor helps
determine the position of the bow of the boat
in the water. Correct trim angle will help im-
prove performance and fuel economy while
reducing strain on the engine. Correct trim
angle depends upon the combination of
boat, engine, and propeller. Correct trim is
also affected by variables such as the load in
the boat, sea conditions, and running speed.
WARNING
 
EWM00740  
Excessive trim for the operating condi-
tions (either trim up or trim down) can
cause boat instability and can make
steering the boat more difficult. This in-
creases the possibility of an accident. If
the boat begins to feel unstable or is hard
to steer, slow down and/or readjust the 
trim angle.
ZMU03108
ZMU02301
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