Yamaha C40 Manual

 
Operation 
36 
EMU27881 
Adjusting trim angle 
Power trim and tilt models
WARNING
 
EWM00750  
 
Be sure all people are clear of the out-
board motor when adjusting the tilt an-
gle, also be careful not to pinch any
body parts between the drive unit and
clamp bracket. 
 
Use caution when trying a trim position
for the first time. Increase speed gradu-
ally and watch for any signs of instabil-
ity or control problems. Improper trim
angle can cause loss of control. 
 
Use the power tilt switch located...

 
Operation 
37 
“” (down).
Make test runs with the trim set to different
angles to find the position that works best for
your boat and operating conditions.
NOTE:
 
To adjust the trim angle while the boat is
moving, use the power trim and tilt switch lo-
cated on the remote control device or tiller 
handle, if equipped. 
EMU27911 
Adjusting boat trim 
When the boat is on plane, a bow-up attitude
results in less drag, greater stability and effi-
ciency. This is generally when the keel line of
the boat is...

 
Operation 
38 
sion with obstructions, and also to reduce
salt corrosion.
WARNING
 
EWM00220  
Be sure all people are clear of the out-
board motor when tilting up and down,
also be careful not to pinch any body
parts between the drive unit and engine 
bracket.
WARNING
 
EWM00250  
Leaking fuel is a fire hazard. If there is a
fuel joint on the outboard motor, discon-
nect the fuel line or close the fuel cock if
the engine will be tilted for more than a 
few minutes. Otherwise fuel may leak.
CAUTION:...

 
Operation 
39 
4. Push the tilt support knob into the clamp
bracket or pull the tilt support lever to-
ward you to support the engine.
WARNING
 
EWM00260  
After tilting the outboard motor, be sure
to support it with the tilt support knob or
tilt support lever. Otherwise the outboard
motor could fall back down suddenly if oil
in the power trim and tilt unit loses pres- 
sure. 
5. Models equipped with trim rods: Once
the outboard motor is supported with the
tilt support lever, press the power trim
and...

 
Operation 
40 
3. Push the power tilt / power trim and tilt
switch “” (down) to lower the outboard
motor to the desired position. 
EMU28060 
Cruising in shallow water 
The outboard motor can be tilted up partially
to allow operation in shallow water. 
EMU28090 
Power trim and tilt models / power tilt 
models 
The outboard motor can be tilted up partially
to allow operation in shallow water.
WARNING
 
EWM00660  
 
Place the gear shift in neutral before
setting up for shallow water cruising. 
 
Return...

 
Operation 
41 
2. Slightly tilt the outboard motor up to the
desired position using the power trim / tilt
switch.3. To return the outboard motor to the nor-
mal running position, press the power
trim / tilt switch and slowly tilt the out-
board motor down. 
EMU28191 
Cruising in other conditions 
Cruising in salt water 
After operating in salt water, wash out the
cooling water passages with fresh water to
prevent them from becoming clogged with
salt deposits.
NOTE:
 
For cooling system flushing...

 
42 
Maintenance 
EMU28217 
Specifications 
Dimension: 
Overall length:
40TR 646 mm (25.4 in)
50TR 670 mm (26.4 in)
Overall width:
40TR 350 mm (13.8 in)
50TR 360 mm (14.2 in)
Overall height L:
1319 mm (51.9 in)
Transom height L:
533 mm (21.0 in)
Weight (without propeller) L:
86.0 kg (190 lb) 
Performance: 
Full throttle operating range:
4500–5500 r/min
Maximum output:
40TR 29.4 kW@5000 r/min (40 
HP@5000 r/min)
50TR 36.8 kW@5000 r/min (50 
HP@5000 r/min)
Idling speed (in neutral):
800  
± 
50 r/min...

 
Maintenance 
43 
Spark plug:
25.0 Nm (18.4 ft-lb) (2.55 kgf-m)
Propeller nut:
35.0 Nm (25.8 ft-lb) (3.57 kgf-m) 
EMU28222 
Transporting and storing 
outboard motor
WARNING
 
EWM00690  
 
Leaking fuel is a fire hazard. When
transporting and storing the outboard
motor, close the air vent screw and fuel
cock to prevent fuel from leaking. 
 
USE CARE when transporting fuel tank,
whether in a boat or car. 
 
DO NOT fill fuel container to maximum
capacity. Gasoline will expand consid-
erably as it warms...

 
Maintenance 
44 
ventilated place, not in direct sunlight. 
EMU28301 
Procedure 
EMU28372 
Flushing in a test tank 
1. Wash the outboard motor body using
fresh water. For further information, see
page 46.
2. Fill the fuel tank with fresh fuel and add
one ounce of “Yamaha Fuel Conditioner
and Stabilizer” (Part No. LUB-FUELC-
12-00) to each gallon of fuel.
NOTE:
 
The use of “Yamaha Fuel Conditioner and
Stabilizer” eliminates the need to drain the
fuel system. Consult your Yamaha dealer or
other...

 
Maintenance 
45 
cowling. 
EMU28410 
Lubrication (oil injection models) 
1. Grease the spark plug threads and in-
stall the spark plug(s) and torque to
proper specification. For information on
spark plug installation, see page 49.
2. Fill the oil tanks. This prevents the for-
mation of condensation. For models with
a remote oil tank, it may be necessary to
manually override the control unit to
completely fill the engine oil tank.
3. Change the gear oil. For instructions,
see page 55. Inspect the oil...