JLG 601S ANSI Service Manual - Manual (Page 107)

SECTION 3 - CHASSIS & TURNTABLE
3120746 – JLG Lift – 3-67
a. Loosen jam nut
b. Screw the adjustment screw all the way in, then
back out 1/2 turn.
c. Tighten jam nut.
Try to start the engine.
NOTE: If EMS switch is pulled on for an extended period of
time, i.e. 1 to 2 minutes, without attempting to start
the engine, the choke will start to open due to electri-
cal heating.
Checking the Ignition
If the engine tries to start but spits and sputters:
1. Check the Oil Pressure Switch:
a. Check for voltage from N.C. (normally closed)
terminal to common ground while cranking the
engine. (what should the voltage be?)
b. Jump all three posts at the oil pressure switch,
then see if the engine will start.
c. If the engine starts after jumping the posts,
replace oil pressure switch (JLG p/n: 4360405)
2. Check the Spark Plugs for presence of spark. If
there is no spark at the plugs during cranking:
a. Overspeed relay not activating.
b. Check the ignition module red/green wire for 12
volts.
c. Check the white/black wire coming from the 8-
pin connector (pin-H) that runs to the overspeed
relay on terminal 85 for proper ground.
3. Ignition module may have failed.
a. Ignition module series: AA, AB and FA prior to
date code-1889 may need replaced. (refer to:
Ford Technical Bulletin # FF-91-99)
b. Check the vacuum advance tube attached to the
ignition module for secure connection.
Try to start the engine.
3.22 CHECKING THE FUEL
The engine may not be getting fuel to the carburetor
1. Check the fuel shutoff solenoid
a. Must have 12 volt while cranking the engine.
2. Check the electric fuel pump
a. Must have 12 volts or be able to hear the pump
running while cranking the engine.
b. Check fuel pressure, must have a minimum of
2-4lbs.
3. Check Fuel Filter:
NOTE: Some JLG machines have a fuel return line between
the fuel pump and carburetor, if this return line is
pinched and the fuel pressure increases this indi-
cates a clogged fuel filter.
4. Check the fuel pump supply line for any obstruction.
Try to start the engine.
NOTE: JLG Industries Inc. recommends the use of engine
block heaters and or cold weather packages for
machines intended for use in 0° F (-18° C) or colder
conditions. Refer to the JLG Parts Manual for specify
options for your machine.
(Machines equipped with non-hydrostatic gear pump
or non-proportional drive systems, i.e. H models,
60HA should consider having block heaters and or
cold weather packages installed for use in 20° F (-
6.5° C) and colder conditions.