Mercury HP 500 EFI Bravo XR/XZ/III, User Manual, Page: 57 / 148

53 500 EFI Bravo
OPERATION
Power Trim
Power Trim allows the operator to adjust the drive angle, while
underway, to provide the ideal boat angle for varying load and water
conditions.
CAUTION
Engine must maintain a minimum of 20 psi of water pressure
and should not exceed 30 psi maximum at 4800 to 5200 RPM
as measured at the lower block drain position (either side of
the block).
IMPORTANT: In order to significantly raise the strength of the
Hi-Performance heavy duty gimbal ring, the trim limit and elec-
tric trim indicator sending unit mounting position has been
eliminated. Having no trim limit switch permits the operator to
trim the drive to any position at any throttle setting.
CAUTION
Use extreme caution when operating with drive unit raised.
Severe damage to the drive unit may result if unit is raised be-
yond the gimbal ring support flanges at engine speeds above
1200 rpm. It is recommended that Bravo heavy duty gimbal
rings use manual indicators to help keep the operator aware
of the drive positioning.
1 In most cases, best overall performance is obtained with the
drive unit adjusted so the boat bottom will run at a 3
°
to 5
°
angle
to the water.
2 Trimming Drive Unit UP/OUT Can:
•
Generally increase top speed.
•
Increase clearance over submerged objects or a shallow bottom.
•
Cause boat to accelerate and plane off slower.
•
In excess, cause boat porpoising” (bouncing) or propeller ventila-
tion.
•
Cause engine overheating if trimmed UP/OUT to a point where
any cooling water intake holes are above the water line.
(continued on next page)