JLG 660SJ ANSI Service Manual - Manual (Page 118)

SECTION 3 - CHASSIS & TURNTABLE
3-64 – JLG Lift – 3120718
Checking the Carburetor
After cranking the engine for a period of time there may be
white smoke noticed coming out of the exhaust tube. This
is an indication the engine is receiving fuel and is in a
“flooded” condition.
NOTE: Make sure the choke is adjusted using the asterisk
(*). There is also a zero (0) stamped on the choke.
The zero (0) is used for assembly purposes and is
not to be used as an adjustment reference.
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)