Propellers; Performance Issues And Propellers - Monterey M3 Owner's Manual

Propulsion System

3.5 Propellers

The outdrive can be equipped with a single pro-
peller or dual, counter rotating propellers that
convert the engine's power into thrust, depending
on engine and outdrive selected for your boat.
Propellers come in a variety of styles, diameters
and pitches. Pitch is the theoretical distance trav-
eled by the propeller in each revolution.
The propeller(s) that will best suit the normal
needs of your boat will depend somewhat on your
application and expected average load. Propeller
sizes are identified by a number or code stamped
on the prop. Always repair or replace a propeller
immediately if it has been damaged. A damaged
and therefore out of balance propeller can cause
vibration that can be felt in the boat and could
damage the outdrive gear assembly.
Please refer to the outdrive owner's manual for
specific information on propellers and the proper
installation procedure.

3.6 Performance Issues and Propellers

It is extremely important that the boat is propped
to run at or very near the recommended top RPM
with an average load. If the top RPM is above or
below the recommended range, the propellers(s)
must be changed to prevent loss of performance
and possible engine damage.
The engine can be damaged and the warranty
voided if the boat is not propped correctly. Al-
ways consult your Monterey or authorized en-
gine service dealer when making changes to the
propeller(s) or if the boat does not run near the
top recommended RPM.
Your boat was shipped with a propeller or propel-
lers that typically provide optimum performance
for your boat. However there are factors that can
affect performance and propeller requirements.
NOTICE:
Before changing propellers to correct boat
performance problems, be sure other factors
such as engine tuning, bottom and running
gear growth, etc. are not the source of per-
formance changes. Always be sure the load
conditions are those normally experienced
before changing propellers.
Typical Mercruiser Bravo III Propellers
Volvo DP Propellers
• The addition of heavy equipment like excessive
gear, additional coolers, etc.,
additional load on the engine. Consequently,
a different propeller or propellers may be
required.
• If the boat ran in the required RPM range
when it was new and you have not added
any additional gear or heavy equipment and
have not damaged a propeller, there is a good
chance the propeller or propellers are not the
problem.
• Boats operated at high altitudes (above 2000
feet). Engines operated at high altitudes will
not be able to develop as much horse power
as they do at or near sea level. Consequently,
a different propeller or propellers may be
required.
MONTEREY
BOATS
will cause
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