Installation
31
EMU26903
Installation
The information presented in this section is intended as ref-
erence only. It is not possible to provide complete instruc-
tions for every possible boat and motor combination. Proper
mounting depends in part on experience and the specific
boat and motor combination.
WARNING
EWM01591
Overpowering a boat could cause severe instability.
Do not install an outboard motor with more horsepow-
er than the maximum rating on the capacity plate of
the boat. If the boat does not have a capacity plate,
consult the boat manufacturer.
Improper mounting of the outboard motor could result
in hazardous conditions such as poor handling, loss of
control, or fire hazards. For permanently mounted
models, your dealer or other person experienced in
proper rigging should mount the motor.
EMU35812
Mounting the outboard motor
The outboard motor should be mounted so that the boat is
well balanced. Otherwise, the boat could be hard to steer.
For single-engine boats, mount the outboard motor on the
centerline (keel line) of the boat.
For twin engine boats, mount the outboard motors equidis-
tant from the centerline.
For triple engine boats, mount the center outboard motor on
the centerline (keel line), and the port side and starboard side
outboard motors equidistant from the center outboard mo-
tor.
Consult your Yamaha dealer or boat manufacturer for further
information on determining the proper mounting location.
EMU26937
Mounting height (boat bottom)
The mounting height of your outboard motor affects its effi-
ciency and reliability. If it is mounted too high, propeller ven-
tilation may occur, which will reduce propulsion due to
excessive propeller slip, and the water intakes for the cool-
ing system may not get an adequate water supply, which
can cause engine overheating. If the engine is mounted too
low, water resistance (drag) will increase, thereby reducing
engine efficiency and performance.
Most commonly, an outboard motor should be mounted so
that the anti-cavitation plate is in alignment with the bottom
of the boat. The optimum mounting height of the outboard
motor is affected by the boat/motor combination and the de-
sired use. Test runs at different heights can help determine
the optimum mounting height. Consult your Yamaha dealer
or boat manufacturer for further information on determining
the proper mounting height.
NOTICE
ECM01635
Make sure that the idle hole is high enough to prevent
water from entering the engine even if the boat is sta-
tionary with the maximum load.
Incorrect engine height or obstructions to the smooth
flow of water (such as the design or condition of the
boat, or accessories, such as transom ladders or
depth finder transducers) can create airborne water
spray while the boat is cruising. If the outboard motor
is operated continuously in the presence of airborne
water spray, enough water could enter the engine
through the air intake opening in the top cowling to
cause severe engine damage. Remove the cause of
the airborne water spray.
1. Center line (keel line)
1. Center line (keel line)
1
1
1. Center line (keel line)
1. Idle hole
ZMU05957
1
1
U6GR30E0.book Page 31 Thursday, April 12, 2018 9:28 AM
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2019 Yamaha Motor Corporation, U.S.A.
