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Operation
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
29
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 35.
EMU30172
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.
ECM00800
CAUTION:
Failure to follow the break-in procedure
could result in reduced engine life or
even severe engine damage.
EMU27080
Procedure for 4-stroke models
Run the engine under load (in gear with a
propeller installed) as follows.
1.
For the first hour of operation:
Run the engine at 2000 r/min or at ap-
proximately half throttle.
2.
For the second hour of operation:
Run the engine at 3000 r/min or at ap-
proximately three-quarter throttle.
3.
For the next eight hours of operation:
Avoid continuous operation at full throt-
tle for more than five minutes at a time.
4.
After the first 10 hours:
Operate the engine normally.
EMU27101
ZMU01874
EWM00080
WARNING
If any item in the preoperation check is
your
Yamaha
Breaking in engine
Preoperation checks
dealer
or
boat
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