Adjusting Boat Trim - Yamaha F15 Owner's Manual

Operation
DN
To raise the bow ("trim-out"), tilt the outboard
motor up.
To lower the bow ("trim-in"), tilt the outboard
motor down.
Make test runs with the trim set to different
angles to find the position that works best for
your boat and operating conditions.
TIP:
Stay within the trim operating angle when
trimming the outboard motor using the power
tilt system.
58
UP
DN
ZMU05579
ZMU04899
UP
EMU27912

Adjusting boat trim

When the boat is on plane, a bow-up attitude
results in less drag, greater stability and effi-
ciency. This is generally when the keel line of
the boat is up about 3 to 5 degrees. With the
bow up, the boat may have a greater tenden-
cy to steer to one side or the other. Compen-
sate for this as you steer. When the bow of
the boat is down, it is easier to accelerate
from a standing start onto plane.
Bow Up
Too much trim-out puts the bow of the boat
too high in the water. Performance and econ-
omy are decreased because the hull of the
boat is pushing the water and there is more
air drag. Excessive trim-out can also cause
the propeller to ventilate, which reduces per-
formance further, and the boat may "por-
poise" (hop in the water), which could throw
the operator and passengers overboard.