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Helm Control Systems
4.6 Steering System
Power Assist Hydraulic Steering
Hydraulic Steering System
Most power assisted steering systems on single
engine or twin engine boats without the joystick
option are hydraulic and comprised of two hydraulic
circuits: a manual system, which is the control
element, and a hydraulic power assist pump, which
is the working element.
The manual system is hydraulic and made of three
main components: the helm assembly, hydraulic
hoses and the steering cylinder. The uid reservoir
for the system is built into the helm assembly or
assist pump and the helm acts as a pump. Turn-
ing of the steering wheel, pumps uid through the
hydraulic hoses and activates the hydraulic steering
cylinder causing the motor or motors to turn. A
slight clicking sound may be heard as the wheel is
turned. This sound is the opening and closing of
valves in the helm pump unit and is normal.
The power system is an electronically controlled,
12 volt hydraulic pump that boosts uid pressure
being sent from the helm pump to the steering
cylinder to provide “Power” for the steering system
which results in much easier eort at the steering
wheel, even under heavy loads. In the event of
a power loss or failure of the hydraulic steering
pump, the steering system will automatically revert
to a manual hydraulic system. The manual system
operates as described previously in this section and
will require more eort on the steering wheel to
turn the motors.
Hydraulic Steering Cylinders and Tie Bar
Single Engine Steering Cylinder
Single outboard engines with hydraulic power assist
steering are equipped with one hydraulic steering
cylinder mounted on the engine that is connected
directly to the engine tiller arm.
Mercury Steering System Power Assist Pump
SeaStar Steering System Power Assist Pump
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