JLG 80HX_HX+6_HXER ANSI Service Manual User Manual
Page 64
SECTION 3 - CHASSIS & TURNTABLE
3-26
– JLG Lift –
3120271
Check-Out and Initial Start-Up Procedures
Before proceeding, familiarize yourself with the locations
of the various adjustment pots.
Adjustments
High engine
Mid engine
Start lockout
Over speed lockout
Factory adjust Gain
High Engine:
This adjustment is made by turning the 1/8" brass screw
clockwise (CW) to increase speed, and counterclockwise
(CCW) to decrease speed. The adjustment range of the
high engine pot is 25 turns, each turn will change engine
speed by about 100 to 200 RPMS. This pot is protected by
a slip clutch at each end and will not be harmed by mod-
erate over-adjustment. However the governor will not
function when the pot is past full travel. If you suspect that
you may have over-adjusted the high engine pot, or have
lost track of where you are, turn the pot 25 to 30 turns out
(CCW), then turn in (CW) 10 turns. This will get you back
into the range you should be in. Make the high engine
adjustment first, then gain, then reset high engine.
Gain:
This adjustment is made by turning the plastic screw
clockwise (CW to increase governor sensitivity, counter-
clockwise (CCW) to decrease sensitivity. The adjustment
range of the Factory pot is about 3/4 of a turn, AND OVER-
TURNING WILL BREAK THE INTERNAL STOPS, making
further adjustments impossible. Too much gain will cause
instability and the engine will pulsate, Not enough gain will
make the engine slow to respond to load requirements,
and at first appears to be a good setting when operating
directional functions other than drive. The engine will
accelerate right up to the set RPMS and stop at that
point.The problem with this type of gain setting is that
when a large load is applied (usually thru drive) and then
suddenly unloaded, the engine will be slow to respond in
decreasing RPMS. This will cause the engine to over rev
and then at times, will activate the over speed cutout and
shut the engine off. The ideal gain setting will provide a
compromise between quick response and good stability.
This will usually show up as 1 to 3 engine pulsation’s
before leveling out at the set RPMS when going from idle
to high engine.
Mid engine:
This adjustment is made by turning the 1/8" brass screw
clockwise (CW) to increase speed, and counterclockwise
(CCW) to decrease speed. The adjustment range of the
Mid engine pot is about 25 turns, each turn will change
engine speed by about 100 to 200 RPMS. THE pot is pro-
tected by an slip clutch at each end and will not be
harmed by moderate over adjustment. However, the gov-
ernor will not function when the pot is past full travel. If you
suspect that you have over adjusted the Mid engine pot,
or have lost track of where you are, turn the pot 25 turns
out (CCW), then turn in (CW), 15 turns. This will get you
back into the range you should be in. Make all adjust-
ments before setting the mid engine.
Start lockout:
This adjustment is made by turning the 1/8" brass screw
clockwise (CW) to increase speed and counterclockwise
(CCW) to decrease speed. The adjustment range of the
Start lockout pot is about 25 turns, each turn will change
engine speed by about 100 to 200 RPMS. This pot is pro-
tected by a slip clutch at each end and will not be harmed
by moderate over-adjustment. However, the governor will
not function when the pot is past full travel. If you suspect
that you may have over-adjusted the Start lockout pot, or
have lost track of where you are, turn the pot to 25 to 30
turns in (CW), Then turn out (CCW) 8 1/2 turns. This will
get you back into the range you should be in. Start lock-
out should normally not have to be adjusted. Normally
startout should occur at around 500 RPM. If while crank-
ing the engine seems to stop momentarily then reengages
the starter, turn the adjustment in (CW) 1/4 to 1/2 turn at a
time until the engine will crank with out locking out start. If
the starter engages while the engine is running, check the
idle RPMS before adjusting the governor. On the 800
series, this should be 1000 RPMS. Do not set the RPMS
above 1100 RPMS as this will cause engine shut down
problems that will be similar to dieseling.