KONRAD 520 - Installation Guidelines

1) Ensure that the propeller height is performed
according to guidelines detailed in diagrams
10-410 (Figures A and B on pages 9 and 10
in this manual). The height of the propeller
is critical to a successful application. If the
propeller centerline is too low, excessive
drag can occur based on transom assembly
location. Intermediate spacers are available
for special concerns.
2) Ensure that the water ow to the propeller
is clear and consistent without interruptions.
Protrusions on the hull surface create a neg-
ative pressure area and induce turbulence.
Turbulence can cause severe propeller inef-
ciency and excessive torsional vibration.
Common problems are:
• Water pickup
• Sonar transducers
• Retrotted surfaces which are not
properly faired or smoothed
• Any hull shape which does not
provide smooth transition
• In heavy applications, the bow can
produce turbulence if the attitude
of the vessel is weighted forward.
• Improper listing of the vessel due
to weight distribution
Installation Guidelines
3) Ensure that the vessel center of gravity is
properly placed. Excessive weight forward
or aft can signicantly affect performance
and the efciency of the propeller.
4) Ensure that the stern drive is trimmed to
the correct level. While undertrimming can
cause premature u-joint wear, overtrimming
can cause propeller inefciency, porpoising,
and premature gear wear.
500 SERIES INSTALLATION MANUAL JANUARY 2010PAGE 8