Theory Of Operation; Power Source; Hydraulic System; Electrical System - Genie S-60 Service Manual

Third Edition • First Printing

Power Source

The Genie S-60 and Genie S-65 are powered by
either a Gasoline/LPG engine or one of two diesel
engines. The Gasoline/LPG option uses a Ford
LRG-425 EFI rated at 70 horsepower @ 2500
rpm. The diesel options include a Deutz
F4L1011F rated at 56 horsepower @ 3000 rpm,
and a Perkins 704-30 rated at 63 horsepower @
2600 rpm.

Hydraulic System

All machine functions are performed by the
hydraulic system. The hydraulic system is divided
into two groups: Boom/Steer functions and Drive
functions.
Boom/Steer functions are powered by a single-
section gear pump, rated at 12.3 gpm
(46.6 L/min). When the engine is running, this
pump supplies hydraulic fluid under pressure to
the function manifold, where the directional and
flow control valves are located. To protect from
over-pressurization of the Boom/Steer system, the
pump is provided with a pressure relief valve, set
at 2900 psi (200 bar) on S-65 Models, and 2600
psi (179 bar) S-60 Models.
Drive functions are powered by a bi-directional,
variable output piston pump rated at 0 to 30.3 gpm
(0 to 114.7 L/min) @ 2500 rpm. Two internal 3500
psi (241 bar) relief valves are used to prevent
over-pressurization of the closed loop drive
system.
The boom lift cylinder, boom extend cylinder,
platform leveling slave cylinder, platform rotator
and jib boom cylinder (S-65 models) incorporate
counterbalance valves to prevent movement in the
event of a hydraulic line failure.
Part No. 65196

Theory Of Operation

Electrical System

Boom/Steer functions are accomplished by
moving a toggle switch or a controller, which
sends voltage to the appropriate directional control
valve. These directional valves determine which
direction the hydraulic fluid will travel. The volume
of hydraulic fluid is determined by either a
proportional valve or flow regulator valve. A
proportional valve receives a variable voltage
signal and delivers more hydraulic fluid as the
voltage increases. A flow regulator valve is a
mechanical valve and delivers a predetermined
amount of hydraulic fluid.
Drive forward or reverse is accomplished by
pressing down the foot switch in the platform and
moving the drive controller (joystick) in the
appropriate direction. When activated, the drive
controller completes a circuit to the Electronic
Displacement Controller (EDC). The EDC
regulates drive pump displacement in direct
relation to the drive controller position. A
horsepower limiter printed circuit board (located in
the platform control box) is provided to maintain
engine RPM as drive system loads become
greater. This is done by sensing engine RPM (via
an AC tap on the alternator) and limiting the
amount of current supplied to the drive controller/
EDC, which destrokes the pump, reducing pump
output.
Genie S-60 & Genie S-65
Section 3 • Theory of Operation
3 - 1