Yamaha C40 Manual

 
Basic components 
16 
EMU26151 
Power trim and tilt switch on bottom 
engine cowling 
The power trim and tilt switch is located on
the side of the bottom engine cowling. Press-
ing the switch “” (up) trims the outboard
motor up, then tilts it up. Pressing the switch
“” (down) tilts the outboard motor down
and trims it down. When the switch is re-
leased, the outboard motor will stop in its
current position.
WARNING
 
EWM01030  
Use the power trim and tilt switch located
on the bottom engine cowling...

 
Basic components 
17 
EMU26261 
Trim rod (tilt pin) 
The position of the trim rod determines the
minimum trim angle of the outboard motor in
relation to the transom. 
EMU26340 
Tilt support lever for power trim and 
tilt or hydro tilt model 
To keep the outboard motor in the tilted up
position, lock the tilt support lever to the
clamp bracket. 
EMU26372 
Top cowling lock lever(s) (turn type) 
To remove the engine top cowling, turn the
lock lever(s) and lift off the cowling. When in-
stalling the...

 
Basic components 
18 
EMU26470 
Tachometer 
This gauge shows the engine speed and has
the following functions. 
EMU26491 
Digital tachometer 
The tachometer shows the engine speed
and has the following functions.
NOTE:
 
All segments of the display will light momen-
tarily after the main switch is turned on and 
will return to normal thereafter.
NOTE:
 
The water separator and engine trouble
warning indicators only operate when the en-
gine is equipped with the appropriate func- 
tions. 
EMU26540 
Oil...

 
Basic components 
19 
rious engine damage will occur. 
EMU26581 
Overheat warning indicator (digital 
type) 
If the engine temperature rises too high, the
warning indicator will start to blink. For fur-
ther information on reading the indicator, see
page 20.
CAUTION:
 
ECM00050  
Do not continue to run the engine if the
overheat warning indicator is on. Serious 
engine damage will occur. 
EMU26610 
Trim meter 
This gauge shows the trim angle of your out-
board motor.
NOTE:
 
Memorize the trim angles...

 
Basic components 
20 
engine has been run. It can be set to show
the total number of hours or the number of
hours for the current trip. The display can
also be turned on and off. 
 
Changing the display format 
 
Pressing the “” (mode) button chang-
es the display format in the following pat-
tern: 
 
Total hours 
→ 
Trip hours 
→ 
Display off 
 
Resetting the trip hours 
 
Simultaneously pressing the “” (set)
and “” (mode) buttons for more than
1 second while the trip hours are displayed
resets...

 
Basic components 
21 
EMU26845 
Oil level warning and oil filter 
clogging warning 
Oil injection models 
This engine has an oil level warning system.
If the oil level falls below the lower limit, the
warning system will activate. 
Activation of warning device 
 
Engine speed will automatically decrease
to about 2000 r/min. 
 
The oil level warning indicator will light. 
 
The buzzer will sound (if equipped on the
tiller handle, remote control box, or main
switch panel).
If the warning system has...

 
Basic components 
22
1. Oil filter
ZMU03366
1
✩✦✯✬✤✲✲✣ ✥✥ 	
 


 

 
23 
Operation 
EMU26901 
Installation
CAUTION:
 
ECM00110  
Incorrect engine height or obstructions
to smooth water flow (such as the design
or condition of the boat, or accessories
such as transom ladders or depth finder
transducers) can create airborne water
spray while the boat is cruising. Severe
engine damage may result if the motor is
operated continuously in the presence of 
airborne water spray.
NOTE:
 
During water testing check the buoyancy of
the boat, at rest, with its maximum load.
Check...

 
Operation 
24 
motor greatly affects the water resistance. If
the mounting height is too high, cavitation
tends to occur, thus reducing the propulsion;
and if the propeller tips cut the air, the engine
speed will rise abnormally and cause the en-
gine to overheat. If the mounting height is too
low, the water resistance will increase and
thereby reduce engine efficiency. Mount the
outboard motor so that the anti-cavitation
plate is in alignment with the bottom of the
boat.
NOTE:
 
 
The optimum...

 
Operation 
25 
board (if packed). For details, consult
your Yamaha dealer.
WARNING
 
EWM00650  
Avoid using bolts, nuts or washers other
than those contained in the engine pack-
aging. If used, they must be of at least the
same quality of material and strength and
must be tightened securely. After tighten-
ing, test run the engine and check their 
tightness. 
EMU27020 
Breaking in engine 
Your new engine requires a period of break-
in to allow mating surfaces of moving parts to
wear in evenly. Correct...