JLG 600A Service And Maintenance Manual page 200

3.22 SPARK ARRESTER CLEANING INSTRUCTIONS
1. Remove the cleanout plug in the bottom of spark
arrester (muffler).
2. Without causing deformation (or any type of damage to
the spark arrester) repeatedly tap on the arrester near
the cleanout plug. This may be enough to begin
drainage of the spark trap.
3. An industrial vacuum cleaner can do a complete job at
this point.
a. Or, IN A SAFE AREA, start the engine. Then alternate
between low idle and high idle for two to three min-
utes.
b. Or, operate the engine as required by the applica-
tion for two to three minutes.
4. Install the cleanout plug.
3.23 DUAL FUEL SYSTEM (GAS ENGINE ONLY)
IT IS POSSIBLE TO SWITCH FROM ONE FUEL SOURCE TO THE OTHER WITHOUT
ALLOWING THE ENGINE TO STOP. EXTREME CARE MUST BE TAKEN AND THE
FOLLOWING INSTRUCTIONS MUST BE FOLLOWED.
Changing from Gasoline to LP Gas
1. Start the engine from the ground control station.
2. Open the hand valve on the LP gas supply tank by
turning counterclockwise.
3. While engine is operating on GASOLINE under a no load
condition, place FUEL SELECT switch at Platform Control
to LP position.
Changing from LP Gas to Gasoline
1. With engine operating on LP under a no-load condition,
position FUEL SELECT switch at Platform Control Station
to GASOLINE position.
2. Close hand valve on LP gas supply tank by turning
clockwise.
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SECTION 3 - CHASSIS & TURNTABLE
3.24 FORD EFI ENGINE
Performing Diagnostics
1. Verify the complaint and determine if it is a deviation
from normal operation.
2. Once the complaint has been verified, preliminary
checks can be done. Conduct a thorough visual
inspection, be alert for unusual sounds or odors, and
gather diagnostic trouble code information.
3. Perform a system check that will verify the proper
operation of the system in question and check for recent
information updates.
4. If a diagnostic trouble code (DTC) is stored, contact a JLG
distributor to make an effective repair.
5. If no DTC is stored, select the symptom from the
symptom tables and follow the diagnostic path or
suggestions to complete the repair.
6. After the repair has been made and validated for proper
operation, the old part should be momentarily re-
installed to verify that it was indeed the source of the
problem.
7. If no matching symptom is available, analyze the
complaint and develop a plan for diagnostics utilizing
the wiring diagrams, technical assistance, and repair
history.
8. Intermittent conditions may be resolved by using a
check sheet to pinpoint the circuit or electrical system
component. Some diagnostic charts contain Diagnostic
Aids which give additional information about a system.
Be sure to use all of the information that is available to
you.
Visual/Physical Engine Inspection Check
Perform a careful visual and physical engine inspection before
performing any diagnostic procedure. Perform all necessary
repairs before proceeding with additional diagnosis, this can
often lead to repairing a problem without performing unnec-
essary steps. Use the following guidelines when performing a
visual/physical inspection check.
• Inspect engine for modifications or aftermarket equipment
that can contribute to the symptom; verify that all electri-
cal and mechanical loads or accessory equipment is "OFF"
or disconnected before performing diagnosis.
• Inspect engine fluids for correct levels and evidence of
leaks.
• Inspect vacuum hoses for damage, leaks, cracks, kinks and
improper routing, inspect intake manifold sealing surface
for a possible vacuum leak.
• Inspect PCV valve for proper installation and operation.
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