Breaking In Engine; Procedure For 4-Stroke Models - Yamaha F115 Owner's Manual

1. Center line (keel line)
EMU26930
Mounting height (boat bottom)
To run your boat at optimum efficiency, the
water resistance (drag) of the boat and out-
board motor must be made as little as possi-
ble. The mounting height of the outboard
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 mounting height of the out-
G
board motor is affected by the boat/motor
combination and the desired use. Test
runs at different heights can help deter-
mine the optimum mounting height. Con-
sult
manufacturer for further information on de-
termining the proper mounting height.
For instructions on setting the trim angle of
G
the outboard motor, see page 48.
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Your new engine requires a period of break-
in to allow mating surfaces of moving parts to
wear in evenly. Correct break-in will help en-
sure proper performance and longer engine
life.
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CAUTION:
Failure to follow the break-in procedure
could result in reduced engine life or
even severe engine damage.
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Procedure for 4-stroke models

Run the engine under load (in gear with a
propeller installed) for 10 hours as follows.
1. First hour:
Run the engine at 2000 r/min or at ap-
proximately half throttle.
2. Second hour:
Run the engine at 3000 r/min or at ap-
proximately three-quarter throttle.
3. Remaining eight hours:
Run the engine at any speed. However,
avoid operating at full throttle for more
than 5 minutes at a time.
4. After the first 10 hours:
Operate the engine normally.
ZMU01874
Operation
your Yamaha dealer

Breaking in engine

or boat
39