Piper Dakota Maintenance Manual page 495

7. Remove magneto drive gear backlash by turning propeller opposite to normal rotation approximately
40° past No. 1 firing position. Turn propeller in direction of normal rotation up to No. 1 firing position
of 23° BTC.
8. Remove timing window plug from most convenient side of magneto housing. Remove plug from rotor
viewing window in center of housing.
9. Turn rotating magnet drive shaft in normal direction of magneto rotation until red distributor tooth is
centered in timing hole. Check to ensure that built-in pointer just ahead of rotor viewing window
aligns with R or L mark on rotor depending on whether magneto is for right or left hand rotation as
specified by magneto data plate.
10. While holding magneto in No. 1 firing position (tooth in window center and pointer over R or L mark
on rotor), install magneto to engine and loosely clamp in position.
11. Attach red lead from 11-9110 timing light to left switch adapter lead, green timing light lead to right
switch adapter lead, and black timing light lead to magneto housing. (Refer to figure 74-4)
An internal timing tolerance is allowed when adjusting two main
breakers. Therefore, one of the main breakers may open slightly
before the other. Magneto-to-engine tuning should be
accomplished using the first main breaker to open as a reference
point when engine is in firing position for No. 1 cylinder. This
will ensure that ignition created by either spark plug will not
occur prior to desired engine firing point.
12. If both timing lights light, indicating breaker contacts are closed, proceed to step 13. If either, or both
are OFF, proceed as follows:
a. Turn entire magneto to right until both timing lights are ON.
b. Ensure that red painted distributor gear tooth is still visible in timing hole.
13. Rotate entire magneto in direction of rotor rotation until one timing light goes out. Then, evenly
tighten magneto mounting clamps.
14. Back engine up approximately 10° and carefully bump engine forward while observing timing lights.
15. At No. 1 cylinder firing position, same timing light mentioned in step 13 should go out. Continue
turning engine in its normal direction of rotation until other timing light goes out. It should not be
more than 3 engine degrees later than first light.
16. Repeat steps 12, 13, and 14 until condition described in step 15 is obtained.
17. Complete tightening of magneto securing clamps by torquing to 150 inch-pounds.
18. Recheck timing once more and if satisfactory, disconnect timing light. Remove adapter leads.
19. Reinstall plugs in timing inspection holes and tighten to a torque of 12 to 15 inch-pounds.
20. Loosely install harness with clamps or brackets.
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
—NOTE—
2J3
74 - 11 - 00
Page - 74-07
Reissued: August 1, 1986