General Guidelines; Installation Height Check - Honda BF75D Manual

General Guidelines

Install the outboard motor on the center of the transom
securely and be sure that the boat is well-balanced.
CENTER LINE
BOAT TRANSOM
As a general rule, the outboard should be installed so
the anti-cavitation plate is parallel to the boat transom.
If the boat transom angle is less than 8˚, the BF75D or
BF90D anti-cavitation plate will not be parallel to the
boat bottom when trimmed to the lowest position.
IDLE PORT
ANTI-CAVITATION PLATE
The BF75D and BF90D outboard motors are designed
to be installed on boat transom with the following
transom board thickness.
Boat transom board thickness: 41 – 70 mm (1-5/8 –
2-3/4 in)
TRANSOM ANGLE
15

Installation Height Check

NOTICE
The water can damage the outboard motor when it
enters the idle port. Be sure to set the outboard motor
installation height according to the following
procedure.
• The outboard motor installation height shall be ± 25
mm ( ± 1 in) when the transom height of the boat is
subtracted from the transom height of the outboard
motor.
Note that this dimension is just the standard.
Optimal installation height differs depending on the
boat type and shape of the bottom of the boat. Refer
to the boat maker's recommended installation height
and determine the optimal installation height by test
cruising the boat.
• If the outboard motor is installed at too low (deep)
position;
— It reduces operating stability.
— It reduces high speed sailing performance.
— Water splashed over the wash board can be jetted
out and fan out the stern of the board.
— It lacks airiness of the boat.
— It gets heavy steering.
• If the outboard motor is installed at too high
(shallow) position, it causes cavitation when sailing
on the choppy water or sailing at high speed, and the
boat does not sail smoothly.
1) Use a pencil and tape measure to locate center line.
Put one end of the tape measure on a chine and
place the other end on the upper edge of the
transom, somewhere past the "visual" center.
Place a mark on the transom and record the
distance measured.
BOAT TRANSOM
KEEL
2) Measure the boat transom height.
CENTER LINE
BOAT TRANSOM HEIGHT