JLG 40H Service Manual - Manual (Page 48)

SECTION 2 - PROCEDURES
2-28
– JLG Lift – 3120240
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 conditions. 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 per-
formance.
This kind of trouble usually falls into three main catego-
ries:
1. Actual Governor malfunction.
2. Governor installation problems and improper adjust-
ment.
3. Governor not tuned or adjusted for engine/applica-
tion.
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.
d. By carefully varying engine speed, you should
be able to cause the Governor arm to pause
momentarily near the middle of its travel. This
engine speed is the speed for which the Gover-
nor is adjusted. If grossly incorrect, reset High
Engine Pot.
e. With the engine running at low speed, move the
Governor arm throughout its stroke by hand.
You should feel a constant smooth force in the
on direction. No binding or rubbing should be
felt within the Governor.
If steps 1a. thru 1e. can be accomplished as described,
the Governor is probably OK. It recognizes underspeed,
overspeed, onspeed and is not binding internally.
If the above steps cannot be accomplished satisfactorily,
there is probably an actual Governor malfunction.
a. Governor is unable to move fuel system freely
(not enough Actuator force available). If Gover-
nor doesn’t move fuel system to on far enough