Oshkosh Corporation JLG 260MRT, Service Maintenance Manual

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SECTION 2 - PROCEDURES
3121801 – JLG Lift – 2-23
2.15 AUTOMATIC CHOKE - FIELD
ADJUSTMENT (DF-750)
Inspection
NOTE: All automatic choke assemblies have been pre-set to
operate between -7°C and 38°C (20°F and 100°F)
with little or no adjustment. If the machine will be
operated for prolong use outside these temperature
ranges, adjustments could be made to improve per-
formance of the engine.
The machine will take time to warm up and you may
experience low power or rough running for the first
few minutes of operation or until the engine warms
up. LET THE ENGINE WARM UP.
Make sure that the choke shaft operates freely and does
not bind. this can be done without removing the air horn
by rotating the bronze coupling with an eraser on a pencil
or by removing the vacuum pull off line at the manifold
and supply a small amount of vacuum to the hose. the
choke rod should move freely using either method.
Adjustments
NOTE: If the choke rod is binding make sure the support
bracket is straight.
1. There are two adjustments Vertical (loosening the air
horn nuts) and Horizontal (loosening the bracket to
adaptor screws). These two adjustments should
resolve any binding problem.
2. To adjust the choke at 21°C (70°F) ambient, remove
the air horn and reinstall the nut that holds the choke
and support bracket securely making sure the
choke moves freely.
3. Loosen the 3 top cover screws and rotate the top
cover till the choke butterfly is closed with 1/32 in
space between the plate and the wall of the carbure-
tor.
4. If the ambient temperature is less then 21°C (70°F)
the top cover counter should be rotated CCW 1
mark for every -15°C (5°F) less then 21° C (70°F).
5. If the ambient temperature is more then 21°C (70°F)
the top cover counter should be rotated CW 1 mark
for every -15°C (5°F) less then 21°C (70°F)
.
Reassembly
Reassemble the air horn making sure the choke is not
binding, test to insure that none of the settings have
moved and the choke is not binding.
The vacuum pull off should be set such that when vacuum
is applied to the choke system the choke butterfly is full
open.
NOTE: If the machine starts and stalls immediately or if it is
extremely cold, limiting the choke pull off to 75% to
90% may improve the performance of the machine.
No adjustment is normally required.
Diesel Engine
NOTE: Never run the fuel tank dry. Diesel engines cannot be
restarted after running out of fuel until the fuel sys-
tem has been air-vented or ‘bled’ of air. See the
Kubota Instruction Manual for the proper procedure.
Figure 2-21. Automatic Choke Adjustment (DF-750)