Piper SEMINOLE PA-44-180, Maintenance Manual

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— Note —
The use of the timing light unit, P/N 11-9110-1 available from Bendix will simplify
the internal timing procedure and breaker synchronization.
10. Connect the timing light black lead to any unpainted surface of the magneto.
11. Connect the red timing light lead to the left breaker terminal and the green lead to the right main breaker
terminal. (Refer to Figure 74-8.)
12. Loosen rotor holding tool and move the rotor back a few degrees; then move it forward. Both lights should
go out to indicate opening of the main breakers when the timing pointer is indicating within the width of the
“R” or “L” mark and the red painted teeth are centered in timing windows.
13. If breaker timing is not correct, loosen cam securing screw (refer to Figure 74-9) and unseat main breaker
cam from taper. Using 11-3031 Retaining Ring Pliers inserted in holes in cam, rotate main breaker cam in
direction of rotation until left main breaker points just open and press cam onto taper. Tighten screw to seat
main breaker cam.
14. Loosen rotor holding tool to turn rotating magnet back a few degrees; then turn rotating magnet in normal
direction of rotation. Timing light should go out when timing pointer is aligned with “R” or “L” (“E” gap)
mark. Lock rotating magnet in position where points just open.
15. Loosen right main breaker securing screws and position breaker so cam follower is pressed against cam
with points closed. Tighten contact assembly securing screws to prevent contact assembly from bouncing
back when moved. Using a small mallet and drift, tap right breaker in until points just open.
16. Turn rotating magnet back a few degrees; then turn rotating magnet in normal direction of rotation. Both
timing lights should go out within one degree or half the width of “R” or “L” mark on rotor. If breakers are
not properly synchronized, reset right breaker.
17. Check right main breaker contact for 0.016 + .004 inch point opening and torque right breaker contact
securing screws to 20-25 inch-pounds. If point opening is out of limits, repeat timing procedure setting left
main breaker opening at .016 + .002 inch. If right contacts open beyond .020 inch, set left contacts closer to
.018 inch. If right contacts open less than .012 inch, set left contacts closer to .014 inch.
18. Using timing light, recheck timing to insure main breakers open within one-half the width of “R”or “L”
mark and that retard breaker opens at correct degree setting. Using a wire feeler gauge, check left main
breaker for .016 + .002 inch point opening and right main breaker and retard breaker for .016 ± .004 inch
point opening.
— Note —
If correct breaker timing cannot be achieved, refer to Bendix Service Bulletin No. 605
or remove magneto and have it overhauled.
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
7 4 - 11 - 0 3
Page 74-10
Revised: May 15, 1989
3G3
PIPER AIRCRAFT