Yamaha F 40 User Guide

							 
Maintenance 
55 
Yamaha genuine parts and accessories are
available from your Yamaha dealer. 
						

							 
Maintenance 
56 
EMU28522 
Maintenance chart 
Frequency of maintenance operations may be adjusted according to the operating condi-
tions, but the following table gives general guidelines. Refer to the sections in this chapter for
explanations of each owner-specific action.
NOTE:
 
When operating in salt water, turbid or muddy water, the engine should be flushed with clean 
water after each use.
The “” symbol indicates the check-ups which you may carry out yourself.
The “” symbol indicates work to be carried out by your Yamaha dealer. 
Item ActionsInitial Every
10 hours 
(1 month)50 hours 
(3 
months)100 
hours (6 
months)200 
hours (1 
year)  
Anode(s) (external)Inspection / replace-
ment
Anode(s) (internal)Inspection / replace-
ment
Battery Inspection / charging
Cooling water pas-
sagesCleaning
Cowling clamp Inspection
Fuel filter (disposable)Inspection / replace-
ment
Fuel system Inspection
Fuel tank (Yamaha por-
table tank)Inspection / cleaning
Gear oil Change
Greasing points Greasing
Idling speed (carbure-
tor models)Inspection
Power trim and tilt unit Inspection
Propeller and cotter pinInspection / replace-
ment
Shift link / shift cable Inspection / adjustment
ThermostatInspection / replace-
ment
Throttle link / throttle 
cable / throttle pick-up 
timingInspection / adjustment 
						

							 
Maintenance 
57 
EMU28874 
Maintenance chart (additional) 
EMU28910
NOTE:
 
When using lead or high-sulfur gasoline, inspecting valve clearance may be required more 
frequently than every 500 hours. 
Water pumpInspection / replace-
ment
Engine oil Inspection / change
Oil filter (cartridge) Change
Spark plug(s)Cleaning / adjustment / 
replacement
Timing beltInspection / replace-
ment
Valve clearance (OHC, 
OHV)Inspection / adjustment 
Item ActionsEvery
500 hours (2.5 years) 1000 hours (5 years) 
Timing belt Replacement
Exhaust guide, exhaust 
manifoldInspection / replace-
ment 
Item ActionsInitial Every
10 hours 
(1 month)50 hours 
(3 
months)100 
hours (6 
months)200 
hours (1 
year) 
						

							 
Maintenance 
58 
EMU28931 
Greasing 
Yamaha marine grease (Water resistant grease) 
F40 
EMU28952 
Cleaning and adjusting spark plug
WARNING
 
EWM00560  
When removing or installing a spark plug,
be careful not to damage the insulator. A
damaged insulator could allow external
sparks, which could lead to explosion or 
fire. 
The spark plug is an important engine com-
ponent and is easy to inspect. The condition
of the spark plug can indicate something
about the condition of the engine. For exam-
ple, if the center electrode porcelain is very
white, this could indicate an intake air leak or
carburetion problem in that cylinder. Do notattempt to diagnose any problems yourself.
Instead, take the outboard motor to a
Yamaha dealer. You should periodically re-
move and inspect the spark plug because
heat and deposits will cause the spark plug
to slowly break down and erode. If electrode
erosion becomes excessive, or if carbon and
other deposits are excessive, you should re-
place the spark plug with another of the cor-
rect type.
Before fitting the spark plug, measure the
electrode gap with a wire thickness gauge;
ZMU04081
 
Standard spark plug:
DPR6EA-9 
						

							 
Maintenance 
59 
adjust the gap to specification if necessary.
When fitting the plug, always clean the gas-
ket surface and use a new gasket. Wipe off
any dirt from the threads and screw in the
spark plug to the correct torque.
NOTE:
 
If a torque-wrench is not available when you
are fitting a spark plug, a good estimate of
the correct torque is 1/4 to 1/2 a turn past fin-
ger-tight. Have the spark plug adjusted to the
correct torque as soon as possible with a 
torque-wrench. 
EMU28962 
Checking fuel system
WARNING
 
EWM00060  
Gasoline and its vapors are highly flam-
mable and explosive. Keep away from
sparks, cigarettes, flames, or other 
sources of ignition.
WARNING
 
EWM00910  
Leaking fuel can result in fire or explo-
sion. 
 
Check for fuel leakage regularly. 
 
If any fuel leakage is found, the fuel
system must be repaired by a qualified
mechanic. Improper repairs can make 
the outboard unsafe to operate. 
Check the fuel lines for leaks, crack, or mal-
function. If a problem is found, your Yamaha
dealer or other qualified mechanic should re-
pair it immediately.
Checkpoints 
 
Fuel system parts leakage 
 
Fuel line joint leakage 
 
Fuel line cracks or other damage 
 
Fuel connector leakage 
1. Spark plug gap
2. Spark plug I.D. mark (NGK) 
Spark plug gap:
0.8–0.9 mm (0.031–0.035 in)
Spark plug torque:
18.0 Nm (13.3 ft-lb) (1.84 kgf-m)
ZMU04082 
						

							 
Maintenance 
60 
EMU28990 
Checking fuel filter 
Check the fuel filter periodically. The fuel fil-
ter is a one piece, disposable type. If foreign
matter is found in the filter, replace it. For re-
placement of the fuel filter, consult your
Yamaha dealer. 
EMU29041 
Inspecting idling speed
WARNING
 
EWM00451  
 
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.
CAUTION:
 
ECM00490  
This procedure must be performed while
the outboard motor is in the water. A
flushing attachment or test tank can be 
used. 
A diagnostic tachometer should be used for
this procedure. Results may vary depending
on whether testing is conducted with the
flushing attachment, in a test tank, or with the
outboard motor in the water.
1. Start the engine and allow it to warm up
fully in neutral until it is running smooth-
ly.
NOTE:
 
Correct idling speed inspection is only possi-
ble if the engine is fully warmed up. If not
warmed up fully, the idle speed will measure
higher than normal. If you have difficulty ver-
ifying the idle speed, or the idle speed re-
quires adjustment, consult a Yamaha dealer 
or other qualified mechanic.
2. Verify whether the idle speed is set to
specification. For idle speed specifica-
tions, see page 49. 
EMU29073 
Changing engine oil
WARNING
 
EWM00760  
 
Avoid draining the engine oil immedi-
ately after stopping the engine. The oil
is hot and should be handled with care
to avoid burns. 
 
Be sure the outboard motor is securely
fastened to the transom or a stable 
stand.
CAUTION:
 
ECM00970  
 
Do not overfill the oil, and be sure the
outboard motor is upright (not tilted)
when checking and changing the en-
gine oil. 
 
If the oil level is above the upper level
mark, drain until the level meets the
specified capacity. Overfilling the oil 
could cause leakage or damage.
CAUTION:
 
ECM01240  
Change the engine oil after the first 10
hours of operation, and every 100 hours
or at 6-month intervals thereafter. Other- 
wise the engine will wear quickly.
ZMU04083 
						

							 
Maintenance 
61
NOTE:
 
Change the engine oil when the oil is still 
warm.
1. Put the outboard motor in an upright po-
sition (not tilted).
2. Prepare a suitable container that holds a
larger amount than the engine oil capac-
ity. Loosen and remove the drain screw
while holding the container under the
drain hole. Then remove the oil filler cap.
Let the oil drain completely. Wipe up any
spilled oil immediately.
3. Put a new gasket on the oil drain screw.
Apply a light coat of oil to the gasket and
install the drain screw.
NOTE:
 
If a torque wrench is not available when you
are installing the drain screw, finger tighten
the screw just until the gasket comes into
contact with the surface of the drain hole.
Then tighten 1/4 to 1/2 turn more. Tighten
the drain screw to the correct torque with a 
torque wrench as soon as possible.
4. Add the correct amount of oil through the
filler hole. Install the filler cap.
5. Start the engine and watch to make sure
the low oil pressure warning indicator (if
equipped) turns off. Make sure that
there are no oil leaks.
CAUTION:
 
ECM00680  
If the low oil pressure warning indicator
does not turn off or if there are oil leaks,
stop the engine and find the cause. Con-
tinued operation with a problem could
cause severe engine damage. Consult
your Yamaha dealer if the problem can- 
1. Drain screw 
Drain screw tightening torque:
18.0 Nm (13.3 ft-lb) (1.84 kgf-m)
ZMU04084
1
ZMU04085
 
Recommended engine oil:
4-stroke outboard motor oil
Engine oil quantity (excluding oil filter):
2.0 L (2.11 US qt) (1.76 Imp.qt) 
1. Oil filler cap
1
ZMU04086 
						

							 
Maintenance 
62 
not be located and corrected. 
6. Turn off the engine and wait 3 minutes.
Recheck the oil level using the dipstick
to be sure the level falls between the up-
per and lower marks. Fill with oil if it is
below the lower mark, or drain to the
specified level if it is above the upper
mark.
7. Dispose of used oil according to local
regulations.
NOTE:
 
 
For more information on the disposal of
used oil, consult your Yamaha dealer. 
 
Change the oil more often when operating
the engine under adverse conditions such 
as extended trolling. 
EMU29112 
Checking wiring and connectors 
 
Check that each grounding wire is properly
secured. 
 
Check that each connector is engaged se-
curely. 
EMU29120 
Exhaust leakage 
Start the engine and check that no exhaust
leaks from the joints between the exhaust
cover, cylinder head, and body cylinder. 
EMU29130 
Water leakage 
Start the engine and check that no water
leaks from the joints between the exhaust
cover, cylinder head, and body cylinder. 
EMU29140 
Engine oil leakage 
Check for oil leaks on the around the engine.
NOTE:
 
If any leaks are found, consult your Yamaha 
dealer. 
EMU29163 
Checking power trim and tilt / power 
tilt system
WARNING
 
EWM00430  
 
Never get under the lower unit while it
is tilted, even when the tilt support lever
is locked. Severe injury could occur if
the outboard motor accidentally falls. 
 
Make sure no one is under the outboard 
motor before performing this test. 
1. Check the power trim and tilt unit / power
tilt unit for any sign of oil leaks.
ZMU02058
ZMU04087 
						

							 
Maintenance 
63 
2. Operate each of the power trim and tilt
switches / power tilt switches to check
that all switches work.
3. Tilt the outboard motor up and check
that the trim and tilt rod / the tilt rod is
pushed out completely.
4. Check that the trim and tilt rod / the tilt
rod is free of corrosion or other flaws.
5. Tilt the outboard motor down. Check
that the trim and tilt rod / the tilt rod oper-
ates smoothly.
NOTE:
 
Consult your Yamaha dealer if any operation 
is abnormal. 
EMU29171 
Checking propeller
WARNING
 
EWM00321  
You could be seriously injured if the en-
gine accidentally starts when you are
near the propeller. 
 
Before inspecting, removing, or install-
ing the propeller, remove the spark
plug caps from the spark plugs. Also,
place the shift control in neutral, turn
the main switch to “” (off) and re-
move the key, and remove the lanyard
from the engine stop switch. Turn off
the battery cut-off switch if your boathas one. 
 
Do not use your hand to hold the pro-
peller when loosening or tightening the
propeller nut. Put a wood block be-
tween the anti-cavitation plate and the
propeller to prevent the propeller from 
turning. 
Checkpoints 
 
Check each of the propeller blades for
wear, erosion from cavitation or ventila-
tion, or other damage. 
 
Check the propeller shaft for damage. 
 
Check the splines / shear pin for wear or
damage. 
 
Check for fish line tangled around the pro-
peller shaft. 
1. Trim and tilt rod
1
ZMU04088
ZMU04089
ZMU01897 
						

							 
Maintenance 
64 
 
Check the propeller shaft oil seal for dam-
age.
NOTE:
 
If the shear pin equipped: it is designed to
break if the propeller hits a hard underwater
obstacle to help protect the propeller and
drive mechanism. The propeller will then
spin freely on the shaft. If this happens, the 
shear pin must be replaced. 
EMU30660 
Removing the propeller 
EMU29194 
Spline models 
1. Straighten the cotter pin and pull it out
using a pair of pliers.
2. Remove the propeller nut, washer, and
spacer (if equipped).3. Remove the propeller and thrust wash-
er. 
EMU30670 
Installing the Propeller 
EMU29231 
Spline models
CAUTION:
 
ECM00340  
 
Be sure to install the thrust washer be-
fore installing the propeller, otherwise
the lower case and propeller boss
could be damaged. 
 
Be sure to use a new cotter pin and
bend the ends over securely. Otherwise
the propeller could come off during op- 
eration and be lost. 
1. Apply Yamaha marine grease or a cor-
rosion resistant grease to the propeller
shaft.
2. Install the spacer (if equipped), thrust
washer, and propeller on the propeller
shaft.
3. Install the spacer (if equipped) and the
washer. Tighten the propeller nut to the
specified torque.
4. Align the propeller nut with the propeller
shaft hole. Insert a new cotter pin in the
hole and bend the cotter pin ends. 
1. Cotter pin
2. Propeller nut
3. Washer
4. Spacer 
5. Propeller
6. Thrust washer
ZMU02063