JLG 601S, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
3120746 – JLG Lift – 3-61
1. Turn ignition switch on. Do not start engine. Actuator
should kick toward max. fuel once, and then imme-
diately return to min. fuel. If not, see Troubleshoot-
ing.
2. Use multimeter to check battery voltage at battery
terminals, and record. Now check voltage at the
machine connection points for terminals A & B of the
8 pin connector on the E-331 (A is +, B is -). Voltage
reading should be the same as at battery. If not, shut
down, and correct wiring.
3. Hold the linkage back by hand, so as to control
engine speed manually. Start engine, set vehicle
controls to obtain High Engine speed, gradually
release the linkage, and adjust the speed-set as
needed to set the speed as desired. If engine speed
surges, reduce Gain a little, as required (CCW).
4. Re-check voltage between terminal A & B as in step
2. Voltage reading should be between 13.5 - 14.6
VDC.
5. Carefully adjust Gain. You are looking for the best
compromise between quick response and good sta-
bility. Make very small adjustments, then load and
unload engine, or pull linkage back slightly and
release. Usually, a good set-up is one that makes 1
to 3 small bounces and then steadies down after a
large change. Too much Gain shows up as a rapid
(once per second) instability, most commonly at
light loads. Too little Gain shows up in large over-
shoots on start-up or large load changes, and gen-
erally sluggish operation.
6. Make final adjustment to the High Engine Pot.
7. Set machine controls to obtain the mid-engine
speed. Adjust the mid-engine pot as needed to
obtain the speed desired.
8. The start lockout adjustment is factory set. If neces-
sary, he starter lockout pot may be adjusted to
obtain dropout of the starter as the engine attains
running speed. Normally this is around 500 RPM.
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:
Governor won’t work.
Governor works, but can’t be set up to give
satisfactory 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:
1. No power.
2. Incorrect linkage, preventing movement.
3. Incorrect electrical hook-up.
4. No speed signal to Governor.
5. 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.