Yamaha C-50, Rigging Manual

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2-16
Outboard Rigging Guide - 2001
Jet Drive Eng. Mtg., Maintenance,
Shift Cable Instruction, Service Info.
obstacles or sharp rocks, you may damage the
boat and motor.
If you do run aground, shut the motor off imme-
diately and drag the boat to deeper water.
Occasionally, on running aground, a small rock
may lodge between the impeller and intake hous-
ing wall as you decrease speed, and the motor will
come to a stop. Neither starter motor nor starter
rope will be able to turn it over. To remove the
jam, you can remove the six screws holding the
water intake housing to free the rock.
Be sure to remove the spark plug wires before
attempting to remove the intake screen.
NOTE: Your jet drive is equipped with a key to
protect it in the event of a rock jam. See
“IMPELLER CLEARANCE SETTING” (page
2-17)
NOTE: Gravel passing through the pump will
wear and round off the leading edges of the
impeller blades. For maximum performance, file
these edges occasionally to keep them as sharp as
when new. See “IMPELLER CLEARANCE
SETTING” (page 2-17).
Intake Blockage
Occasionally, when either holding or proceeding
slowly upstream in a fast-moving shallow area,
you will lose power. This is usually caused by
suction holding flat rocks, lily pads, paper, or
other debris against the intake grille and restrict-
ing water intake. If you can quickly stop the
motor and restart it, this sort of material will fall
away and full power will be restored. If, howev-
er, rocks have been jammed between the grille
bars, with the motor off, they must be removed by
prying them out with a suitable tool.
Mooring
If you tie your boat up at a sandy beach, where the
action of waves causes the boat to rise and fall, be
sure to tip the motor up, out or the water. Failure
to do this will result in the buildup of sand inside
the intake housing, around the impeller. It is
advisable to tie the boat up and shut off the motor
any time it is likely to be idled for a sustained
period.
Throttle Use
As with any outboard, you will get maximum
economy by not running at full throttle. Running
at one-third to one-half throttle, with the boat at a
steep angle, leaving a large wake, will also waste
fuel.
Trim and Tilt Use
It is important for you to learn how to use the
Power Trim and Tilt function properly on those
models equipped with this feature.
The Power Trim and Tilt function is convenient
for use while drifting, and when operating at low
throttle in very shallow areas. When under power,
however, the engine should not be trimmed out in
an effort to gain speed as is done with conven-
tional propeller-drive motors.
When planing, the engine drive shaft should be
either vertical or tucked under and toward the
boat in order to provide a good scoop angle for
the water intake grille. Tilting the motor outward,
beyond a vertical position, reduces the scoop
angle, and can cause impeller slippage, as well as
cavitation burns on the impeller blades.
Manual-tilt models should be adjusted with the
tilt pin to provide a vertical engine position while
under plane. See “TEST RUNNING” (page 2-
13).
WARNING