Governor System; Electronic Governor - Kohler ECV940 Service Manual

Governor System

GOVERNOR
Some engines are equipped with an electronic governor or a mechanical governor. Other engines are equipped
with an electronic throttle body (ETB) that uses a motor and controller to open throttle plate rather than a traditional
mechanical governor or a separate governor control unit.

ELECTRONIC GOVERNOR

Electronic Governor System Designs
As of this revision, there is an original design, a fi eld
installed updated design, and a new updated design.
All designs function in same manner, and both updated
designs have a non-serviceable electrical connection
with a sealed (bonded) GCU module wiring harness
assembly.
Electronic Governor System
Electronic governor regulates engine speed at varying
loads based on a variable input voltage from application
(potentiometer or a single pole, single throw (SPST)
switch).
Typical electronic governor includes:
● Digital linear actuator (DLA).
● Throttle linkage.
● Linkage spring.
● Linkage retaining clip.
● Governor control unit (GCU).
Components
A
B
A DLA
C Throttle Linkage
Throttle Body Lever
E
Adapter
Digital Linear Actuator (DLA)
Energizing bi-directional digital linear actuator coils in
proper sequence, causes threaded shaft to move out
of, or back into rotor, in precise linear increments. When
power is removed, actuator shaft remains in position.
DLA must initialize (fully extend) to move throttle plate to
closed position, and partially open for starting. Correct
adjustment of DLA is critical to achieve full range of
throttle plate movement. See Adjustment.
Governor control unit (GCU) senses engine speed
by pulse voltage inputs from EFI ECU module. GCU
regulates engine speed by variable input voltage from a
customer-supplied source.
86
F
D
E
C
Plastic Linkage
B
Retaining Clip
D Linkage Spring
F Throttle Body
KohlerEngines.com
NOTE: Actual speeds depend on application. Refer to
equipment manufacturer's recommendations.
Potentiometer Specifi cations
Speed Input Voltage
0-1
1-9
9-16
DLA Function
DLA function can be tested and confi rmed using a
stepper motor controller tool. Refer to Tools and Aids.
Testing instructions are included with this tool.
Throttle Linkage
NOTE: Throttle linkage spring must be in place and
installed correctly to ensure proper throttle
operation and performance.
Throttle linkage spring will fully open throttle plate if
linkage becomes detached from DLA. This will create an
overspeed condition causing engine to shut down. DLA
shaft will have to be manually screwed back into body,
and then retracted before reassembling linkage. Detailed
instructions are in steps 4 and 5.
Adjustment
DLA Details
A
G
A DLA
C Clevis
E Clevis Shaft
G Keys
DLA must be in fully retracted position during assembly.
Full range of throttle plate movement will not be
achieved if DLA is partially extended when assembled.
Loosen DLA mounting plate screws located on side
of actuator plate. With throttle linkage secured with a
retaining clip at end of DLA shaft, slide DLA bracket
assembly back until throttle plate is fully open. Torque
mounting plate screws to 10.2 N·m (90 in. lb.).
Engine Speed (RPM)
Low Speed Endpoint
Variable Speed Endpoint
High Speed Endpoint
B
B
C
E
D
F
B Mounting Holes
D Keyway
F Rubber Boot
62 690 05 Rev. H
A
C