Yamaha C40 Manual

							 
General information 
6 
bend that may obstruct the view of other wa-
ter vessels, the operator should sound a pro-
longed blast on the whistle (4 to 6 seconds).
If another vessel is around the bend, it too
should sound the whistle. Even if no reply is
heard, however, the vessel should still pro-
ceed around the bend with caution. If you
navigate such waters with your boat, you will
need to carry a portable air horn, available
from local marine supply stores. 
Fishing vessel right-of-way 
All vessels which are fishing with nets, lines
or trawls are considered to be “fishing ves-
sels” under the International Rules. Vessels
with trolling lines are not considered fishing
vessels. Fishing vessels have the right-of-
way regardless of position. Fishing vessels
cannot, however, impede the passage of
other vessels in narrow channels. 
Sailing vessel right-of-way 
Sailing vessels should normally be given the
right-of-way. The exceptions to this are:
1. When the sailing vessel is overtaking
the power-driven vessel, the power-driv-
en vessel has the right-of-way.
2. Sailing vessels should keep clear of any
fishing vessel.
3. In a narrow channel, a sailing vessel
should not hamper the safe passage of
a power-driven vessel which can navi-
gate only in such a channel. 
Reading buoys and other markers 
The waters of the United states are marked
for safe navigation by the lateral system of
buoyage. Simply put, buoys and markers
have an arrangement of shapes, colors,
numbers and lights to show which side of the
buoy a boater should pass on when navigat-
ing in a particular direction. The markings on
these buoys are oriented from the perspec-
tive of being entered from seaward (the boat-er is going towards the port). This means that
red buoys are passed on the starboard
(right) side when proceeding from open wa-
ter into port, and black buoys are to port (left)
side. When navigating out of port, your posi-
tion with respect to the buoys should be re-
versed; red buoys should be to port and
black buoys to starboard.
Many bodies of water used by boaters are
entirely within the boundaries of a particular
state. The Uniform State Waterway Marking
System has been devised for these waters.
This system uses buoys and signs with dis-
tinctive shapes and colors to show regulato-
ry or advisory information. These markers
are white with black letters and orange
boarders. They signify speed zones, restrict-
ed areas, danger areas, and general infor-
mation.
Remember, markings may vary by geo-
graphic location. Always consult local boat-
ing authorities before driving your boat in
unfamiliar waters.✩✦✯✬✤✲✲✣ ✩ 	
 


 
						

							 
General information 
7 
EMU25540 
Fueling instructions
WARNING
 
EWM00010  
GASOLINE AND ITS VAPORS ARE HIGH-
LY FLAMMABLE AND EXPLOSIVE! 
 
Do not smoke when refueling, and keepaway from sparks, flames, or other
sources of ignition. 
 
Stop engine before refueling. 
 
Refuel in a well-ventilated area. Refuel
portable fuel tanks off the boat. 
 
Take care not to spill gasoline. If gaso-
line spills, wipe it up immediately with
ZMU01708
✩✦✯✬✤✲✲✣ ✪ 	
 


 
						

							 
General information 
8 
dry rags. 
 
Do not overfill the fuel tank. 
 
Tighten the filler cap securely after re-
fueling. 
 
If you should swallow some gasoline,
inhale a lot of gasoline vapor, or get
gasoline in your eyes, get immediate
medical attention. 
 
If any gasoline spills onto your skin, im-
mediately wash with soap and water.
Change clothing if gasoline spills on it. 
 
Touch the fuel nozzle to the filler open-
ing or funnel to help prevent electro- 
static sparks.
CAUTION:
 
ECM00010  
Use only new clean gasoline which has
been stored in clean containers and is not
contaminated with water or foreign mat- 
ter. 
EMU25570 
Gasoline 
If knocking or pinging occurs, use a different
brand of gasoline or premium unleaded fuel. 
Gasohol 
There are two types of gasohol: gasohol con-
taining ethanol and that containing metha-
nol. Gasohol containing ethanol can be used
if ethanol content does not exceed 10% and
the fuel meets minimum octane ratings.
Yamaha does not recommended gasohol
containing methanol because it can cause
fuel system damage or engine performance
problems. 
EMU25650 
Engine oil 
If the recommended engine oil is not avail-
able, another 2-stroke engine oil with an
NMMA-certified TC-W3 rating may be used. 
EMU25690 
Battery requirement
CAUTION:
 
ECM01060  
Do not use a battery that does not meet
the specified capacity. If a battery which
does not meet specifications is used, the
electric system could perform poorly or
be overloaded, causing electric system 
damage. 
For electric start models, choose a battery
which meets the following specifications. 
EMU25711 
Battery specifications 
EMU25742 
Propeller selection 
The performance of your outboard motor will
be critically affected by your choice of propel-
ler, as an incorrect choice could adversely
affect performance and could also seriously
damage the motor. Engine speed depends
on the propeller size and boat load. If engine Recommended gasoline:
Regular unleaded gasoline with a min-
imum octane rating of 86 (Pump Oc-
tane Number) = (R+M)/2
Recommended engine oil:
YAMALUBE 2-stroke outboard motor 
oil
Minimum cold cranking amps (CCA/
SAE):
245.0 A
Minimum marine cranking amps (MCA/
ABYC):
323.0 A
Minimum reserve capacity (RC/SAE):
52 minutes
✩✦✯✬✤✲✲✣ ✫ 	
 


 
						

							 
General information 
9 
speed is too high or too low for good engine
performance, this will have an adverse effect
on the engine.
Yamaha outboard motors are fitted with pro-
pellers chosen to perform well over a range
of applications, but there may be uses where
a propeller with a different pitch would be
more appropriate. For a greater operating
load, a smaller-pitch propeller is more suit-
able as it enables the correct engine speed
to be maintained. Conversely, a larger-pitch
propeller is more suitable for a smaller oper-
ating load.
Yamaha dealers stock a range of propellers,
and can advise you and install a propeller on
your outboard that is best suited to your ap-
plication.
NOTE:
 
Select a propeller which will allow the engine
to reach the middle or upper half of the oper-
ating range at full throttle with the maximum
boat load. If operating conditions such as
light boat loads then allow the engine r/min to
rise above the maximum recommended
range, reduce the throttle setting to maintain 
the engine in the proper operating range.For instructions on propeller removal and in-
stallation, see page 53. 
EMU25770 
Start-in-gear protection 
Yamaha outboard motors or Yamaha-ap-
proved remote control units are equipped
with start-in-gear protection device(s). This
feature permits the engine to be started only
when it is in neutral. Always select neutral
before starting the engine. 
1. Propeller diameter in inches
2. Propeller pitch in inches
3. Type of propeller (propeller mark)
ZMU04606
- x
123
✩✦✯✬✤✲✲✣ ✬ 	
 


 
						

							 
10 
Basic components 
EMU25796 
Main components
NOTE:
 
* May not be exactly as shown; also may not be included as standard equipment on all mod- 
els. 
40, 50 
EMU25802 
Fuel tank 
If your model was equipped with a portable
fuel tank, its function is as follows.
WARNING
 
EWM00020  
The fuel tank supplied with this engine is
its dedicated fuel reservoir and must not
be used as a fuel storage container. Com-
mercial users should conform to relevant
licensing or approval authority regula-
11
14 1512 13
1
2
4
3 5 6 2 789 10
ZMU05014
 
1. Battery cable
2. Anode(s)
3. Propeller*
4. Cooling water inlet
5. Trim tab (anode)
6. Anti-cavitation plate
7. Trim rod
8. Clamp bracket
9. Tilt support lever
10. Top cowling
11. Remote control box (side mount type)*
12. Digital tachometer*
13. Tachometer*
14. Trim meter*15. Fuel tank*✩✦✯✬✤✲✲✣ ✤✣ 	
 


 
						

							 
Basic components 
11 
tions. 
EMU25830 
Fuel joint 
This joint is used to connect the fuel line. 
EMU25841 
Fuel gauge 
This gauge is located on either the fuel tank
cap or on the fuel joint base. It shows the ap-
proximate amount of fuel remaining in the
tank. 
EMU25850 
Fuel tank cap 
This cap seals the fuel tank. When removed,
the tank can be filled with fuel. To remove the
cap, turn it counterclockwise. 
EMU25860 
Air vent screw 
This screw is on the fuel tank cap. To loosen
the screw, turn it counterclockwise. 
EMU26180 
Remote control 
The remote control lever actuates both the
shifter and the throttle. The electrical switch-
es are mounted on the remote control box. 
EMU26190 
Remote control lever 
Moving the lever forward from the neutral po-
sition engages forward gear. Pulling the le-
ver back from neutral engages reverse. The
engine will continue to run at idle until the le-
ver is moved about 35° (a detent can be felt).
Moving the lever farther opens the throttle,
and the engine will begin to accelerate. 
1. Fuel joint
2. Fuel gauge
3. Fuel tank cap
4. Air vent screw
ZMU03157
13
42
 
1. Power trim and tilt switch
2. Remote control lever
3. Neutral interlock trigger
4. Neutral throttle lever
5. Main switch / choke switch
6. Engine stop lanyard switch
7. Throttle friction adjuster
1. Neutral “”
2. Forward “”
3. Reverse “”
4. Shift
5. Fully closed✩✦✯✬✤✲✲✣ ✤✤ 	
 


 
						

							 
Basic components 
12 
EMU26201 
Neutral interlock trigger 
To shift out of neutral, first pull the neutral in-
terlock trigger up. 
EMU26211 
Neutral throttle lever 
To open the throttle without shifting into ei-
ther forward or reverse, put the remote con-
trol lever in the neutral position and lift the
neutral throttle lever.
NOTE:
 
The neutral throttle lever will operate only
when the remote control lever is in neutral.
The remote control lever will operate only
when the neutral throttle lever is in the closed 
position. 
EMU25911 
Tiller handle 
To change direction, move the tiller handle to
the left or right as necessary. 
EMU25922 
Gear shift lever 
Pulling the gear shift lever towards you puts
the engine in forward gear so that the boat
moves ahead. Pushing the lever away from
you puts the engine in reverse gear so that
the boat moves astern. 
6. Throttle
7. Fully open
1. Neutral interlock trigger 
1. Fully open
2. Fully closed✩✦✯✬✤✲✲✣ ✤✥ 	
 


 
						

							 
Basic components 
13 
EMU25941 
Throttle grip 
The throttle grip is on the tiller handle. Turn
the grip counterclockwise to increase speed
and clockwise to decrease speed. 
EMU25961 
Throttle indicator 
The fuel consumption curve on the throttle
indicator shows the relative amount of fuel
consumed for each throttle position. Choose
the setting that offers the best performance
and fuel economy for the desired operation. 
EMU25970 
Throttle friction adjuster 
A friction device provides adjustable resis-
tance to movement of the throttle grip or the
remote control lever, and can be set accord-
ing to operator preference.
To increase resistance, turn the adjuster
clockwise. To decrease resistance, turn the
adjuster counterclockwise.
WARNING
 
EWM00030  
Do not overtighten the friction adjuster. If
there is too much resistance, it could be
difficult to move throttle lever or grip, 
which could result in an accident. 
1. Forward “”
2. Neutral “”
3. Reverse “” 
1. Throttle indicator
ZMU03095
✩✦✯✬✤✲✲✣ ✤✦ 	
 


 
						

							 
Basic components 
14 
When constant speed is desired, tighten the
adjuster to maintain the desired throttle set-
ting. 
EMU25990 
Engine stop lanyard switch 
The lock plate must be attached to the en-
gine stop switch for the engine to run. The
lanyard should be attached to a secure place
on the operator’s clothing, or arm or leg.
Should the operator fall overboard or leave
the helm, the lanyard will pull out the lock
plate, stopping ignition to the engine. This
will prevent the boat from running away un-
der power.
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.
NOTE:
 
The engine cannot be started with the lock 
plate removed. 
EMU26001 
Engine stop button 
To open the ignition circuit and stop the en-
gine, push this button. 
1. Lanyard
2. Lock plate
1. Lanyard
2. Lock plate✩✦✯✬✤✲✲✣ ✤✧ 	
 


 
						

							 
Basic components 
15 
EMU26090 
Main switch 
The main switch controls the ignition system;
its operation is described below. 
 
“”  
(off) 
With the main switch in the “” (off) posi-
tion, the electrical circuits are off, and the key
can be removed. 
 
“”  
(on) 
With the main switch in the “” (on) posi-
tion, the electrical circuits are on, and the key
cannot be removed. 
 
“”  
(start) 
With the main switch in the “” (start) po-
sition, the starter motor turns to start the en-
gine. When the key is released, it returns
automatically to the “” (on) position. 
EMU26141 
Power trim and tilt switch on remote 
control or tiller handle 
The power trim and tilt system adjusts the
outboard motor angle in relation to the tran-
som. Pressing the switch “” (up) trims the
outboard motor up, then tilts it up. Pressing
the switch “” (down) tilts the outboard mo-
tor down and trims it down. When the switch
is released, the outboard motor will stop in its
current position.
NOTE:
 
For instructions on using the power trim and 
tilt switch, see pages 35 and 37.✩✦✯✬✤✲✲✣ ✤