JLG 80HX_HX+6_HXER ANSI Service Manual - Manual (Page 63)

SECTION 3 - CHASSIS & TURNTABLE
3120271 – JLG Lift – 3-25
Examine the system for springs, such as carburetor return
springs. These should be removed. Some automotive car-
buretors (as opposed to industrial carburetors) contain
internal springs for accelerator pumps, etc. These may
make good governing difficult, or even impossible. For
this and other reasons, industrial carburetors are pre-
ferred.
Move the linkage slowly through its travel, and look for
any binding or unexplained forces. Correct any before
going further.
Many “governing” problems are really caused by binding
of the butterfly and its shaft in the carburetor. This is
caused by loading due to vacuum under the butterfly and
atmospheric pressure above when the engine is running.
These forces cannot be felt when the engine is not run-
ning. Therefore, start the engine while carefully controlling
the speed by hand, and feel for binding or air load forces.
Needle bearings on the butterfly shaft are available on
many industrial carburetors to deal with this problem. Any
tendency on the butterfly stick must be corrected.
Mounting-Controller
Select a reasonably cool, dry, and vibration free location.
The rear cover will probably need to be removed during
set-up in order to make adjustments for speed setting and
gain. You may wish to defer final installation until this is
done.
After completing these adjustments, replace cover. Mount
so that water cannot pool on this cover. Always mount the
controller with the strain relief down. This will prevent
water from entering thru the cable, also place the vent
hole in the bottom of the controller down.
Wiring
See wiring diagram for details of hook-up.
Use #16 wire minimum.
Keep all wiring to the Governor as short as is practical.
Go directly from the controller ground terminal (B of the 8
pin connector) by dedicated wire, to the battery “minus”
terminal. If this cannot be done, for some reason, go by
dedicated wire to a very good engine ground.
A properly functioning engine electrical system will supply
13.5 - 14.8 VDC when the engine is running. If wiring size
is adequate, with good connections and proper grounds,
you will get this reading between the wires terminals A & B
of the 8 pin connector when the Governor is controlling
engine speed. Verify this. Improper hook-up can damage
electronics. Re-check wiring before applying power.
Power Distribution
8 Pin Connector
Pin:
a. 12 VDC from the make before break oil pressure
switch. This switch provides power to pin A
when the ignition is on and the engine is running
(no oil pressure), or when the engine is off when
the engines running (has oil pressure).
b. Ground.
c. Tach signal from the engine ignition system.
d. Tach signal from the engine ignition system.
e. Control signal to operate the Actuator.
f. Control signal to operate the Actuator.
g. Removes ground from the start lock out relay
when the engine is running above the start lock
out set point. A 20 turn pot is provided to adjust
this set point. (usually around 500 RPM)
h. Removes ground from the overspeed relay if this
point is exceeded. A 20 turn pot is provided to
adjust this set point.(usually around 5000 RPM)
4 Pin Connector
Pin:
a. Input from the elevation limit switches to allow
high engine to operate.
b. Input from the high engine switch.
c. Input for mid engine from one of the following:
The engine low coolant temperature switch, plat-
form footswitch, or a ground control directional
switch.
d. Provides ground to lockout start when the
engine RPMS exceed the set point.