the WOT RPMs. An engine that is over-revving may
quickly experience catastrophic damage, which will not
be covered under warranty.
If the WOT RPM is lower than the minimum RPM in your
engine’s WOT operating range, the boat is over-propped. In
-
stalling a lower-pitched propeller will increase WOT RPMs.
An engine that is under-revving is “lugging.” This places a
tremendous load on the pistons, crankshaft and bearings
and can cause detonation, piston seizure and other engine
damage, which will not be covered under warranty.
Engines should always be operated within engine
manufacturer guidelines. Failure to do so may
cause significant damage to the engine and drive
train and is not covered under warranty!
Elevation and weather also have a very noticeable ef
-
fect on the wide-open-throttle power of an engine. Since
oxygen gets thinner as elevation increases, the engine
begins to starve for air. Humidity, barometric pressure
and temperature have a noticeable effect on the density
of air since heat and humidity thin the air.
This phenomenon can become particularly apparent
when an engine is propped for use on a cool, dry day in
spring and then is operated on a hot, humid day in sum
-
mer, and does not have the same performance. Although
some performance can be regained by dropping to a
lower-pitch propeller, the basic condition still exists. The
propeller is too large in diameter for the reduced power
output. An experienced marine dealer can determine how
much diameter to remove from a lower-pitch propeller for
specific high-elevation locations.
MasterCraft’s engine manufacturers suggest that con
-
sumers consult with the dealer from whom the boat was
purchased regarding the best propeller for the applica
-
tion in which the boat will primarily be run. However, be
aware that changing the propeller may void the warranty.
Again, working with an authorized MasterCraft dealer is
your best bet to ensure excellent performance.
Unusual Operating Conditions
If the body of water is unknown, talk to the local boaters
about the type of obstacles that may be encountered be
-
neath the water’s surface. Rocks, tree stumps and sand
-
bars are all dangerous and damaging. Be especially wary
of rivers and man-made lakes. Rapidly changing condi
-
tions can cause daily changes in underwater hazards.
Stay well clear of floating debris. What looks to be a small
branch in the water may well turn out to be an entire tree.
When traveling through weedy areas, keep an eye on
the engine temperature gauge. Weeds caught up and
blocking the water flow through the raw water intake or
transmission cooler will cause trouble. Also, after leaving
the weedy area, shift to neutral for a few seconds and
then to reverse for a few seconds to unwind any weeds
that may have wrapped around the propeller.
Docking and Tie-Up
Approach the dock slowly, with the starboard side of the
boat if possible. The natural tendency to torque steer with
the rotation of the propeller at slow speeds makes dock
-
ing easier on that side. Also, use wind and current to your
advantage when docking.
Before tying up the boat, be sure to use enough dock
bumpers to protect the boat from damage. If possible,
tie-up with the bow toward the waves. Use good quality
double-braided nylon line. Tie-up only to the lifting or tie-
down eyes. Never use the handrails or ski pylon.
If the boat is to be moored for a long period of time, use
chafing protectors to protect the gel coat finish. Leave a
little slack in the lines, allowing for some wave movement
or tidal action where applicable.
If the boat is to be kept in or near water for the season,
consider the purchase of a boat lift. These lifts prevent
the build-up of marine growth on the hull as well as pro
-
tecting the boat from damage typical of on-water storage,
such as blistering. Make sure the boat lift supports the
hull correctly. See the next section,
Lifting the Boat.
2008 MasterCraft Owners Manual Page 10-3
