Pulse Generators Installation And Coordinated Timing - Piper PA-44-180 SEMINOLE Maintenance Manual

3. Disconnect the tachomoter cable(s). Tape cable(s) to the aircraft to prevent it/them from falling into
the nacelle.
4. Remove the pulse generator from the bracket by releasing the lock tab washer and unscrewing the
reliance nut. Note location of the electrical plug relative to the plate to facilitate installation .
INSTALLATION AND COORDINATED TIMING OF PULSE GENERATORS. (Refer to Figures 61-5
and 61-6.)
For proper operation of the synchronization system, adjust pulse
generators while attached to the aircraft. If a pulse generator has
been removed, centralize the shaft before installing. Make final
adjustments with the pulse generator loosely attached to its
bracket.
1. With the pulse generator mounting bracket removed from the airplane, loosely attach the generator to
the bracket. The top of the bracket is the bent out edge.
2. Rotate the propeller of the affected engine in its proper direction until the forward outboard cylinder is
at the top dead center (TDC) of its compression stroke.
3. After determining the keyway in the tachomoter drive end of the generator is aligned with the timing
mark on the housing, approximate the position of the mounted bracket and attach the drive cable from
the engine to the inboard side of the generator. If the cable will not line up in the unrotated generator
shaft, rotate the generator on the bracket till the cable fits. Be sure the slot in the tachometer drive end
still lines up with the timing mark.
The lights on the test box for the left and right engine pulse
g e nerators will remain illuminated for several degrees of
r o t ation of the generator housing. The correct timing position,
however, is at the point where the light just comes on.
4. Install the power cable.
5. Positioned as shown in Figure 61-5. Temporarily install the bracket on the nacelle web with a screw on
each side to hold it firmly, and again check that the timing mark and slot align.
6. If the opposing generator was removed proceed with steps 1 through 5 above. If the opposing generator
has not been removed, and the light on the test box for this engine does not come on, proceed as follows:
A. Remove the pulse generator as previously described and, if appropriate, the driven cable
(tachometer cable). Release the lock tab washer, and slightly release the reliance nut so that the
generator can be rotated on its bracket.
B. Temporarily reinstall the assembly with only one screw on each side of the bracket and rotate the
generator housing till the timing mark aligns with the key slot in the shaft.
7. With both engines at the TDC of their compression strokes, check to see if their respective lights on the
test set are ON.
The correct timing position is signified where and when the light
JUST comes on.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
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3D15
61-10-00
Page 61-13
Revised: June 20, 1995