INSTALLATION AND PREDELIVERV
PROPELLER
SELECTION
PROPELLER SELECTION
Refer to PROPELLER
on
p.
258 before installing
propeller.
The correct propeller, under normal load condi-
tions,
will allow the engine to
run
near the mid-
point of the
RPM
operating range at full throttle.
Refer to TECHNICAL
DATA
on
p.
30.
\----3
-6
•
-7-
2-
_Q
1. Percentage
of
horsepower
(kw)
2. Engine RPM
3. Horsepower curve
4.
Full throttle operating range
5. Midpoint
of
full throttle operating
range,
horse·
power rating
in
kilowatts (kw))
6. Engine
is
overloaded at full throttle
7. Engine
is
overspeeding at full throttle
DR1261
~
CAUTION
~
Selection
of
the wrong propeller could
reduce engine service life, affect boat per-
formance,
or
cause serious damage
to
the
powerhead.
54
Procedure
The propeller selection process
is
very important
to
the engine's service life
and
to boat perfor-
mance.
Proceed carefully and thoroughly while
considering the following points:
• During the engine break-in period,
run
the out-
board at wide-open
throttle for only brief periods
of time to check
full-throttle
RPM.
•
Use
an
accurate tachometer to determine the
engine's
full-throttle
RPM
while testing various
propellers.
• Select
a propeller that suits the customer's
application and
allows the engine to
run
near
the midpoint of the
full-throttle operating range
when the boat has a
normal load
in
it.
Refer to
TECHNICAL
DATA
on
p.
30.
•
To
compensate for changes
in
boat loading, the
engine's
full-throttle
RPM
must
be
verified peri-
odically.
• Occasionally,
one propeller will not cover a wide
range of boat applications - water skiing
to
high speed performance boating.
In
such cases,
it
might
be
necessary to have a propeller for
each situation.
IMPORTANT:
If
the propeller blades have too
much pitch, the engine
is
operating below
its
nor-
mal
range at full throttle, power
is
being lost, and
powerhead damage
could occur. If the propeller
blades
have too little pitch, the engine is operating
above
its
normal range at full throttle and damage
from
overspeeding could occur.
~
WARNING
~
When servicing the propeller, always
shift
the outboard
to
NEUTRAL,
turn
the key
switch
OFF,
and
twist
and remove all
spark
plug
leads
so
the engine
cannot
be
started
accidentally.
E
o
o
~
><
~
Qj
~
i:i
E
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