Yamaha 70B Manuel D'utilisation page 22

GB
EMU01395
PROPELLER SELECTION
The performance of your outboard motor
will be critically affected by your choice of
propeller, as an incorrect choice could
adversely affect performance and could
also seriously damage the motor. Engine
speed depends on the propeller size and
boat load. If engine speed is too high or
too low for good engine performance,
this will have an adverse effect on the
engine.
Yamaha outboard motors are fitted with
propellers chosen to perform well over a
range of applications, but there may be
uses where a propeller with a different
pitch would be more appropriate. For a
greater operating load, a smaller-pitch
propeller is more suitable as it enables
the correct engine speed to be main-
tained. Conversely, a larger-pitch pro-
peller is more suitable for a smaller oper-
ating load.
Yamaha dealers stock a range of pro-
pellers, and can advise you and install a
propeller on your outboard that is best
suited to your application.
NOTE:
At full throttle and under a maximum
boat load, the engine's rpm should be
within the upper half of the full throttle
operating range, as listed in "SPECIFICA-
TIONS" on page 4-1. Select a propeller
which fulfills this requirement.
If operating under conditions which allow
the engine's rpm to rise above the maxi-
mum recommended range (such as light
boat loads), reduce the throttle setting to
maintain the rpm in the proper operating
range.
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