EXPORT CONTROLLED RollsRoyce
250B17F SERIES OPERATION AND MAINTENANCE
IGNITION SYSTEMMAINTENANCE PRACTICES
1. General
Maintenance of the ignition system includes: replacing, cleaning and inspecting the spark igniter,
replacing and inspecting the ignition exciter and spark igniter lead, making an ignition check, and
replacing the start counter.
A. Ignition System Check (See Figure 201).
WARNING: MAKE SURE THAT THE IGNITION SWITCH IS OFF BEFORE REMOVING THE
SPARK IGNITER OR SPARK IGNITER LEAD ASSEMBLY AS DANGEROUSLY
HIGH VOLTAGES MAY BE PRESENT. ALLOW FIVE MINUTES AFTER
OPERATION FOR ELECTRICAL DISSIPATION BEFORE DISASSEMBLY.
(1) Disconnect the spark igniter lead from the spark igniter.
CAUTION: TURN THE LEAD NUT AND NOT THE SPARK IGNITER WHEN ASSEMBLING OR
DISASSEMBLING A LEAD AND AN IGNITER WHICH IS NOT INSTALLED ON THE
ENGINE.
(2) Remove the spark igniter. (Refer to para 1.A., 742001.)
(3) Attach the spark igniter lead to the spark igniter.
(4) Apply 28 volts dc across the ignition exciter. Observe or listen for spark.
WARNING: TO PREVENT ELECTRICAL SHOCK DURING INSTALLATION OF THE SPARK
IGNITER AND THE LEAD, ALLOW FIVE MINUTES FOR ELECTRICAL
DISSIPATION FOLLOWING IGNITION OPERATION OR TEST.
(5) When replacing and/or reinstalling a serviceable spark igniter, apply a light coat of antiseize
compound (NS165) to the threads.
(6) Install spark igniter and spark igniter lead on the engine. Tighten the spark igniter to 150200
lb in. (1723 N.m) and lockwire to the fuel nozzle. Tighten the lead to 7090 lb in. (7.910.2
N.m).
740000
Page 201
Sep 15/00
Rolls-Royce Proprietary Data Uncontrolled Printed Copy
EXPORT CONTROLLED RollsRoyce
250B17F SERIES OPERATION AND MAINTENANCE
1. Spark Igniter 8. Bolt (2) 15. Start Counter
2. Ignition Lead 9. Fire Shield 16. Bracket
3. Nut (3) 10. Ignition Exciter 17. Nut (2)
4. Bolt (3) 11. Nut (3) 18. Bolt (2)
5. Clamp (3) 12. Washer (2) 19. Washer
6. Clamp (3) 13. Nut 20. Protective Bracket
7. Nut (2) 14. Washer 21. Screw (2)
Engine Ignition System Assembly
Figure 201
740000
Page 202
Sep 15/00
Rolls-Royce Proprietary Data Uncontrolled Printed Copy
