JLG 450AJ ANSI Service Manual - Manual (Page 70)

SECTION 2 - PROCEDURES
2-52 – JLG Lift – 3120749
9. The overspeed adjustment is factory set. If neces-
sary, it may be readjusted to shut off ignition power
at a different engine speed by means of the over-
speed adjustment pot. The overspeed is simply to
shut down an over revving engine.
NOTE: Overspeed to be set at 4000 - 4500 RPM’s. This is
not a function we test for correct settings. The High
Engine speed must be set before setting the over-
speed.
10. Re-install the back cover on the E-331. Final mount
the controller.
Troubleshooting
We will discuss Troubleshooting in two general catego-
ries:
a. Governor won’t work.
b. Governor works, but can’t be set up to give sat-
isfactory performance.
There is, of course, some overlap between these catego-
ries. Read both sections and apply the fixes that seem
appropriate.
NOTE: During troubleshooting, be prepared to control the
engine manually to prevent overspeeds, etc.
Governor won’t work.
No reaction from Governor. Actuator output arm never
moved, engine off or engine running. Can be caused by:
No power, Incorrect linkage, preventing movement, Incor-
rect electrical hook-up, No speed signal to Governor,
Damaged Controller or Actuator.
1. No power - Use a multimeter to check for 12-15
VDC between terminals A & B on the controller.
Check during engine off and engine running condi-
tions. If voltage is absent or low, check for:
a. Wiring error.
b. Hook-up on wrong side of ballast resistor.
c. Low battery.
d. Bad voltage regulator.
e. Bad ground connection.
f. Corroded terminals.
g. Undersized wiring.
2. Incorrect Linkage - Re-check linkage as discussed
on page 40 and 41. Freedom of movement and lack
of play are important.
3. Incorrect Electrical Hook-up - Re-check all wiring
and connections to the Actuator and Controller
against the supplied schematic.
4. No speed signal to Controller.
a. Check the voltage between terminals C and
ground and D and ground of the 8 pin connector
with the engine running. You should see 5 - 30
VDC.
b. The above checks do not guarantee a good
speed signal, but their absence proves that
there is a problem.
5. Incorrect Electrical Hook-up - If steps 1 - 4 above
have not revealed the problem, the governor may
have been damaged, either in shipping or during
hook-up and test.
Governor reacts, but can’t be set up to give proper
performance.
This kind of trouble usually falls into three main catego-
ries: Actual Governor malfunction, Governor installation
problems and improper installation, or Governor not
tuned or adjusted for engine/application.
NOTE: Assure the engine is operating properly by running
engine manually. The Governor will not control any
poor running engine.
1. Actual Governor Malfunction - The Governor was
engine-tested for proper operation just prior to being
shipped. Unless damaged in shipment or by
improper handing, it should be serviceable. To
check for proper operation proceed as follows:
a. Once again, disconnect fuel system linkage
from Governor output arm and control engine
manually.
b. Start engine, hold at a low speed, Governor arm
should move to full-fuel position.
c. Increase engine speed carefully. At some engine
speed, Governor arm should move to low-fuel
position.