Tilting Up And Down - Yamaha F150A Owner's Manual

Operation
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 perfor-
mance further, and the boat may "porpoise"
(hop in the water), which could throw the op-
erator and passengers overboard.
Bow Down
Too much trim-in causes the boat to "plow"
through the water, decreasing fuel economy
and making it hard to increase speed. Operat-
ing with excessive trim-in at higher speeds
also makes the boat unstable. Resistance at
the bow is greatly increased, heightening the
danger of "bow steering" and making opera-
tion difficult and dangerous.
54
TIP:
Depending on the type of boat, the outboard
motor trim angle may have little effect on the
trim of the boat when operating.
EMU27935

Tilting up and down

If the engine will be stopped for some time or
if the boat is moored in shallows, the outboard
motor should be tilted up to protect the propel-
ler and lower casing from damage by collision
with obstructions, and also to reduce salt cor-
rosion.
EWM00222
WARNING
Make sure that no one is near the outboard
motor when tilting the outboard motor up
or down. Otherwise, body parts could be
crushed between the outboard motor and
the clamp bracket.
EWM00250
WARNING
Leaking fuel is a fire hazard. If there is a
fuel joint on the outboard motor, discon-
nect the fuel line or close the fuel cock if
the engine will be tilted for more than a few
minutes. Otherwise fuel may leak.