Propeller Selection - Mercury SKI Instruction Manual

Propeller Selection

GENERAL INFORMATION
IMPORTANT: Installed propeller must allow engine to run at its specified maximum
wide-open-throttle revolutions per minute (rpm). Use an accurate service tachometer
to verify engine operating rpm.
It is the responsibility of the boat manufacturer and/or the selling dealer to equip the power
package with the correct propeller(s). Specified engine wide-open-throttle (WOT) and oper-
ating rpm range are listed in the "Operation, Maintenance and Warranty Manual" attached
to the engine.
Select a propeller that will allow the engine power package to operate at or near the top end
of the recommended wide-open-throttle operating rpm range with a normal load.
There is a change in rpm between propeller diameter or pitches that is generalized in the
following chart:
MIE Models
Gasoline
If full throttle operation is below the recommended range, the propeller must be changed
to prevent loss of performance and possible engine damage. On the other hand, operating
an engine above the recommended operating rpm range will cause higher than normal wear
and/or damage.
After initial propeller selection, the following common problems may require that the propel-
ler be changed to a lower pitch:
•
Warmer weather and greater humidity cause an rpm loss.
•
Operating in a higher elevation causes an rpm loss.
•
Operating with increased load (additional passengers, pulling skiers, etc.).
For better acceleration, such as is needed for water skiing, use the next lower pitch propel-
ler. However, do not operate at full throttle when using the lower pitch propeller but not pull-
ing skiers.
Because of the many variables of boat design, only testing will determine the best propeller
for a particular application. Available propellers are listed in the "Quicksilver Accessories
Guide."
See "BOAT-IN-THE-WATER TESTS, Maximum RPM Test" in the power package Installa-
tion Manual.
GASOLINE ENGINES SKI MODELS
Diameter or Pitch Change
1 Inch
INDEX
RPM Change
150
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