Checking the ignition, Checking the ignition -68 – JLG 601S Service Manual User Manual
Page 108
SECTION 3 - CHASSIS & TURNTABLE
3-68
– JLG Lift –
3120866
1. Check the choke for ambient temperature setting.
The default ambient temperature setting is 70° F (21°
C), which aligns the asterisk (*) on the choke face
with the reference mark on the side of the choke
housing. The choke should be set at one notch
“clockwise” past the (*) asterisk for every 5 degrees
below 70° F (one notch “clockwise” past the (*)
asterisk for every 2.8 degrees below 21° C). This
adjustment will "richen" the fuel mixture.
2. Check if the choke “butterfly” is stuck by manually
opening and closing by hand.
3. Check the choke pull-off (butterfly stop) screw for
proper adjustment as follows:
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.