Evinrude E-tec 75 HP, Руководство по обслуживанию

Страница: 64 / 344

64
INSTALLATION AND PREDELIVERY
PROPELLERS
PROPELLERS
Propeller Selection
Water testing with various propeller designs and
sizes is the best method of propeller selection.
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. 18.
IMPORTANT:
If the propeller blades have too
much pitch, the engine will operate below its nor-
mal range at full throttle. Power will be lost, and
powerhead damage could occur. If the propeller
blades have too little pitch, the engine will operate
above its normal range and damage from over-
speeding could occur.
When selecting a propeller, consider the following:
•
Use an accurate tachometer to determine the
engine’s full-throttle RPM.
•
The outboard should be trimmed for top speed.
•
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.
•
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.
•
Refer to the
Evinrude/Johnson Genuine Parts
and Accessories Catalog
for propeller styles
and sizes.
•
Right-hand propellers are considered standard
rotation propellers. When propelling a boat for-
ward, the propeller rotates in a right-hand
(clockwise) direction as viewed from the rear.
•
Left-hand propellers are considered counter-
rotation propellers. When propelling a boat for-
ward, the propeller rotates in a left-hand (coun-
terclockwise) direction as viewed from the rear.
CAUTION
Selection of the wrong propeller could
reduce engine service life, affect boat per-
formance, or cause serious damage to the
powerhead.
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
3
1
2
5
4
6
7
1. Right-hand rotation (clockwise)
2. Left-hand rotation (counterclockwise)
000033
WARNING
For dual-outboard installations, always
check to be sure propellers are installed on
the correct engines before aggressively
operating the boat.
2 1