Yamaha 4 Stroke Owners Manual

							Maintenance
56
EMU34451Maintenance chart 2
Item ActionsEvery
1000 hours
Exhaust guide/exhaust 
manifoldInspection or replace-
ment as necessary
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							Maintenance
57
EMU28941Greasing
Yamaha grease A (water resistant grease)
Yamaha grease D (corrosion resistant grease; for propeller shaft)
F4, F6
ZMU06764
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							Maintenance
58
EMU39291Cleaning and adjusting spark plug
The spark plug is an important engine compo-
nent. The condition of the spark plug can indi-
cate something about the condition of the
engine. For example, if the center electrode
porcelain is very white, this could indicate an
intake air leak or carburetion problem in that
cylinder. Do not attempt to diagnose any
problems yourself. Instead, take the outboard
motor to a Yamaha dealer. You should peri-
odically remove and inspect the spark plug
because heat and deposits will cause the
spark plug to slowly break down and erode.
1. Remove the spark plug cap from the
spark plug.
2. Remove the spark plug. If electrode ero-
sion becomes excessive, or if carbon and
other deposits are excessive, you should
replace the spark plug with another of the
correct type. WARNING! When remov-
ing or installing a spark plug, be care-
ful not to damage the insulator. A
damaged insulator could allow exter-
nal sparks, which could lead to explo-
sion or fire.
 [EWM00561]
3. Be sure to use the specified spark plug,
otherwise the engine may not operate
properly. Before fitting the spark plug,
measure the electrode gap with a wire
thickness gauge; replace it if out of spec-
ification.
4. When fitting the plug, wipe off any dirt
from the threads, and then screw it in to
the correct torque.
TIP:
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 finger-
tight. Have the spark plug adjusted to the cor-
rect torque as soon as possible with a torque-
wrench.
EMU39920Checking fuel filter
The fuel filters are located in the filler hole of
the built-in fuel tank and in the bottom cowling.
Check the fuel filters periodically. If foreign
1. Spark plug cap
Standard spark plug:
CR6HSB
ZMU068031
1. Spark plug gap
2. Spark plug part number
3. Spark plug I.D. mark (NGK)
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Spark plug torque:
13.0 Nm (1.33 kgf-m, 9.6 ft-lb)
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							Maintenance
59
material is found in the filters, clean or replace
them. For cleaning or replacement of the fuel
filters, consult a Yamaha dealer.
EMU40140Inspecting idle speed
NOTICE
ECM02230
When checking the engine idle speed,
make sure to supply water to the cooling
water passages by placing the outboard
motor in the water or by using a flushing
attachment or test tank.
To check the engine idle speed, a diagnostic
tachometer is required. For checking or ad-
justment of the engine idle speed, consult a
Yamaha dealer.
EMU39515Changing engine oil
NOTICE
ECM01710
Change the engine oil after the first 20
hours of operation or 3 months, and every
100 hours or at 1-year intervals thereafter.
Otherwise the engine will wear quickly.
Extract the engine oil with an oil changer.
1. Put the outboard motor in an upright po-
sition (not tilted). NOTICE: If the motor
is not level, the oil level indicated on
the dipstick may not be accurate.
[ECM01860]
2. Start the engine. Warm it up and keep the
idle speed for 5-10 minutes.
3. Stop the engine and leave it for 5-10 min-
utes.
4. Remove the top cowling.
5. Remove the oil filler cap.
TIP:
The oil lubrication check window does not in-
dicate the engine oil level. Use the oil lubrica-
tion check window to make sure that the
engine is being lubricated with oil while it is
running.
6. Insert the tube of the oil changer into the
oil filler hole, and then extract the engine
oil completely using the oil changer.
1. Fuel filter
ZMU0676511
1. Oil filler cap
2. Oil lubrication check window
ZMU06766
ZMU06769
12
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							Maintenance
60
7. If the oil changer is not available, remove
the drain screw while holding a container
under the drain hole. Let the oil drain
completely. Wipe up any spilled oil imme-
diately.
8. If the drain screw was removed, install a
new washer and drain screw, and then
tighten the drain screw.
9. Add the correct amount of oil through the
filler hole. NOTICE: Overfilling the oil
tank could cause leakage or damage.
If the oil level is above the upper mark,
extract oil until the oil is between the
upper and lower marks. 
 [ECM02181]
10. Install the oil filler cap and tighten it com-
pletely.
11. Leave the outboard motor for 5-10 min-
utes.
12. Remove the oil filler cap and wipe the at-
tached oil dipstick clean.
13. Install the oil filler cap and tighten it com-
pletely.
14. Remove the oil filler cap again and check
that the oil level on the dipstick is be-
tween the upper and lower marks. If the
oil level is not at the proper level, add or
extract oil until the oil is between the up-
per and lower marks.
15. Start the engine and make sure that there
are no oil leaks. NOTICE: If there are oil
leaks, stop the engine and find the
cause. Consult your Yamaha dealer if
the problem cannot be located and
corrected. Continued operation with a
problem could cause severe engine
damage.
 [ECM02150]
1. Oil changer
1. Drain screw
2. Washer
Engine oil drain bolt:
18.0 Nm (1.84 kgf-m, 13.3 ft-lb)
ZMU067671
1 2
ZMU06768
Recommended engine oil:
4-stroke outboard motor oil
Engine oil quantity:
0.6 L (0.63 US qt, 0.53 Imp.qt)
1. Oil dipstick
2. Upper mark
3. Lower mark
1
2
3
ZMU06737
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							Maintenance
61
16. Dispose of used oil according to local
regulations.
TIP:

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.
17. Install the top cowling.
EMU39771Checking connector and lead
For checking of the following items for the
connectors and leads, consult a Yamaha
dealer.

Check that each connector is connected
securely.

Check that each ground lead is secured
properly.
EMU39301Checking propeller
WARNING
EWM02280
You could be seriously injured if the en-
gine accidentally starts when you are near
the propeller. Before inspecting, remov-
ing, or installing the propeller, place the
gear shift lever in neutral, and remove the
clip from the engine shut-off switch.
Do not use your hand to hold the propeller
when loosening or tightening the propeller
nut. Put a wood block between the anti-cavi-
tation plate and the propeller to prevent the
propeller from turning.Checkpoints

Check each of the propeller blades for ero-
sion from cavitation or ventilation, or other
damage.

Check the propeller shaft for damage.

Check the splines for wear or damage.

Check for fish line tangled around the pro-
peller shaft.

Check the propeller shaft oil seal for dam-
age.
EMU30662Removing propellerEMU39310Spline models
1. Straighten the cotter pin and pull it out us-
ing a pair of pliers.
2. Remove the propeller nut and washer.
WARNING! Do not use your hand to
hold the propeller when loosening the
propeller nut.
 [EWM01890]
1. Propeller shaft
ZMU06879
ZMU06777
1
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							Maintenance
62
3. Remove the propeller and thrust washer.EMU30672Installing propellerEMU39322Spline models
NOTICE
ECM00500
Be sure to use a new cotter pin and bend
the ends over securely. Otherwise the pro-
peller could come off during operation and
be lost.
1. Apply Yamaha grease D (corrosion resis-
tant grease) into the propeller shaft.
2. Install the thrust washer and propeller
onto the propeller shaft. NOTICE: Be
sure to install the thrust washer before
installing the propeller, otherwise the
lower case and propeller boss could
be damaged.
 [ECM01880]
3. Install the washer and tighten the propel-
ler nut until there is no looseness in the
propeller.
4. Align the propeller nut hole with the pro-
peller shaft hole. Insert a new cotter pin in
the holes and bend the cotter pin ends.NOTICE: Do not reuse the cotter pin
installed. Otherwise the propeller can
come off during operation.
 [ECM01890]
TIP:
If the propeller nut hole does not align with the
propeller shaft hole after tightening the pro-
peller nut, tighten the nut further or loosen the
nut to align the holes.
EMU39780Changing gear oil
WARNING
EWM02350
Be sure the outboard motor is securely
fastened to the transom or a stable stand.
You could be severely injured if the out-
board motor falls on you.
1. Put the outboard motor in an upright po-
sition (not tilted).
2. Place a suitable container under the gear
case.
3. Remove the gear oil drain screw and gas-
ket.
1. Cotter pin
2. Propeller nut
3. Washer
4. Propeller
5. Thrust washer
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							Maintenance
63
4. Remove the oil level plug and gasket to
allow the oil to drain completely.
NOTICE: Check the used oil after it
has been drained. If the oil is milky or
contains a large amount of metal par-
ticles, the gear case may be damaged.
Have a Yamaha dealer check and re-
pair the outboard motor.
 [ECM00712]
TIP:
For disposal of used oil, consult your Yamaha
dealer.
5. Using a flexible or pressurized filling de-
vice, inject the gear oil into the gear oil
drain screw hole.6. Put a new gasket on the oil level plug.
When the oil begins to flow out of the oil
level plug hole, insert and tighten the oil
level plug.
7. Put a new gasket on the gear oil drain
screw. Insert and tighten the gear oil
drain screw.
EMU39331Inspecting and replacing anode (ex-
ternal)
Yamaha outboard motors are protected from
corrosion by sacrificial anode. Inspect the ex-
ternal anode periodically. Remove scales
from the surface of the anode. Consult a
Yamaha dealer for replacement of the exter-
nal anode.
NOTICE
ECM00720
Do not paint anodes, as this would render
them ineffective.
1. Gear oil drain screw
2. Oil level plug
Recommended gear oil:
Hypoid gear oil SAE#90
Gear oil quantity:
0.100 L (0.106 US qt, 0.088 Imp.qt)
12ZMU06779
ZMU06780
Tightening torque:
9.0 Nm (0.92 kgf-m, 6.6 ft-lb)
Tightening torque:
9.0 Nm (0.92 kgf-m, 6.6 ft-lb)
1. Anode
ZMU06781
1
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							Trouble Recovery
64
EMU39523
Troubleshooting
This section describes the likely causes and
remedies for problems, such as those in the
fuel, compression, and ignition systems, poor
starting, and loss of power. Please note that
all of the items in this section may not apply to
your model.
If your outboard motor requires repair, bring it
to a Yamaha dealer.
Engine will not start.
Q. Is fuel tank empty?
A. Fill tank with clean, fresh fuel.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.
Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Is fuel pump malfunctioning?
A. Have serviced by a Yamaha dealer.
Q. Is spark plug fouled or of incorrect type?
A. Inspect spark plug. Clean or replace with
recommended type.
Q. Is spark plug cap fitted incorrectly?
A. Check and re-fit cap.
Q. Is spark plug wiring damaged or poorly
connected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Are electrical parts malfunctioning?
A. Have serviced by a Yamaha dealer.
Q. Is clip on engine shut-off cord (lanyard) in-
stalled?A. Install clip to engine shut-off switch.
Q. Are engine inner parts damaged?
A. Have serviced by a Yamaha dealer.
Engine idles irregularly or stalls.
Q. Is fuel system obstructed?
A. Check for pinched or kinked fuel line or oth-
er obstructions in fuel system.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.
Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Are electrical parts malfunctioning?
A. Have serviced by a Yamaha dealer.
Q. Is spark plug gap incorrect?
A. Replace spark plug.
Q. Is spark plug wiring damaged or poorly
connected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Is specified engine oil not being used?
A. Check and replace oil with specified type. 
Q. Is thermostat malfunctioning or clogged?
A. Have serviced by a Yamaha dealer.
Q. Are carburetor adjustments incorrect?
A. Have serviced by a Yamaha dealer.
Q. Is fuel pump malfunctioning?
A. Have serviced by a Yamaha dealer.
Q. Is air vent screw tightened?
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							Trouble Recovery
65
A. Loosen air vent screw.
Q. Is choke knob pulled out?
A. Return to home position.
Q. Is carburetor clogged?
A. Have serviced by a Yamaha dealer.
Q. Is fuel joint connection incorrect?
A. Connect correctly.
Q. Is throttle cable adjustment incorrect?
A. Have serviced by a Yamaha dealer.
Engine power loss.
Q. Is propeller damaged?
A. Have propeller repaired or replaced.
Q. Is propeller pitch or diameter incorrect?
A. Install correct propeller to operate outboard
at its recommended speed (r/min) range.
Q. Is trim angle incorrect?
A. Adjust trim angle to achieve most efficient
operation.
Q. Is outboard motor mounted at incorrect
height on transom?
A. Have outboard motor adjusted to proper
transom height.
Q. Is boat bottom fouled with marine growth?
A. Clean boat bottom.
Q. Is spark plug fouled or of incorrect type?
A. Inspect spark plug. Clean or replace with
recommended type.
Q. Are weeds or other foreign material tan-
gled on gear housing?A. Remove foreign material and clean lower
unit.
Q. Is fuel system obstructed?
A. Check for pinched or kinked fuel line or oth-
er obstructions in fuel system.
Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.
Q. Is spark plug gap incorrect?
A. Replace spark plug. 
Q. Is spark plug wiring damaged or poorly
connected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Are electrical parts malfunctioning?
A. Have serviced by a Yamaha dealer.
Q. Is specified fuel not being used?
A. Replace fuel with specified type.
Q. Is specified engine oil not being used?
A. Check and replace oil with specified type.
Q. Is thermostat malfunctioning or clogged?
A. Have serviced by a Yamaha dealer.
Q. Is air vent screw tightened?
A. Loosen air vent screw.
Q. Is fuel pump malfunctioning?
A. Have serviced by a Yamaha dealer.
Q. Is fuel joint connection incorrect?
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