Kohler COMMAND CH18, Service Manual

Page: 56 / 232

5.23
Section 5
Fuel System and Governor
5
Figure 5-43. Electronic Governor Assembly.
Digital Linear Actuator (DLA)
Energizing the bi-directional digital linear actuator
coils in the proper sequence, causes the threaded shaft
to move out of, or back into the rotor, in precise linear
increments. When power is removed, the actuator
shaft remains in position. The DLA must initialize
(fully extend) to move the throttle plate to the closed
position, and partially open for starting. Correct
adjustment of the DLA is critical to achieve the full
range of throttle plate movement. See Adjustment
Procedure.
1
2
3
4
5
Figure 5-42. Electronic Governor Assembly.
1. Digital Linear Actuator
2. Throttle Linkage
3. Linkage Spring
4. Choke Linkage
5. Throttle Lever Adapter
Governor Control Unit
Electronic Governor
General
The electronic governor regulates engine speed at
varying loads. It consists of a governor control unit,
digital linear actuator and linkage.
Governor Control Unit (GCU) senses engine speed by
pulse voltage inputs from the ignition modules. The
GCU regulates the engine speed by variable input
voltage from a customer-supplied potentiometer or a
single pole, single throw (SPST) switch.
Potentiometer Specifications:
1860 low speed endpoint
variable speed endpoint
3600 high speed endpoint
Wiper Voltage
0-1
1-9
9-16
Engine Speed (RPM)
1860 low speed endpoint
3600 high speed endpoint
Engine Speed (RPM) Switch Position
Open
Closed
SPST Switch Specifications:
GCU Safety Features
In the event of an engine overspeed condition, the
GCU will shut down the engine by grounding the
ignition modules.
The GCU will shut down the engine by grounding the
ignition when power to the GCU is lost.
Linkage
The throttle linkage spring will fully open the throttle
plate if the linkage becomes detached from the DLA.
This will create an overspeed condition causing the
engine to shut down. The DLA shaft will have to be
manually screwed back into the body, and then
retracted before reassembling the linkage.
Adjustment Procedure
The DLA must be in the fully retracted position
during assembly. The full range of throttle plate
movement will not be achieved if the DLA is partially
extended when assembled. Loosen the two DLA
mounting plate screws located on the top of the
actuator plate. With the throttle linkage centered in
the U-Clip at the end of the DLA shaft, slide the DLA
bracket assembly back until the throttle plate is fully
open. Torque the mounting plate screws to
2.5 N·m
(22 in. lb.) .