TM 9-2350-247-20-2
REPLACE AIR BOX HEATER ELECTRODE (M548A3) -- Continued
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4.
Inspect electrode (2) for damaged threads, cracked insulator, and eroded or pitted electrode.
5.
Using a suitable gauge, set nozzle (3) to wire (4) gap at 0.80 inch (2 cm).
6.
Replace any air box heater assembly that shows any of these defects and cannot be repaired.
WARNING
High voltages are involved in this test. This could cause injury to personnel. Do not touch the
ignition coil, air heater body, electrode, or exposed leads during the test.
CAUTION
Do not apply voltage to ignition coil without connecting the output of ignition coil to electrode
and without connecting air box heater body and ignition coil to a common ground.
7.
With air box heater assembly removed from engine, inspect ignition unit for damaged electrical connections.
8.
Connect output of ignition exciter to electrode terminal.
9.
Connect air box heater body and exciter to a common ground.
10. Connect a source of 24-volt direct current to input of exciter.
11. The electric arc generated between electrode tip and air box heater body should be steady with a slight crackling noise.
12. Remove harness boot end from electrode (1). Use a 5/8 inch (16 mm) deep well socket to remove socket from air box
heater assembly (2).
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