JLG 660SJ ANSI Service Manual - Manual (Page 113)

SECTION 3 - CHASSIS & TURNTABLE
3120718 – JLG Lift – 3-59
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.
B. Governor reacts, but can’t be set up to give
proper performance.
This kind of trouble usually falls into three main
categories:
1.Actual Governor malfunction.
2.Governor installation problems and improper
installation.
3.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.
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.