Piper PA-28-161, Maintenance Manual

Page: 928 / 1104

PIPER AIRCRAFT, INC.
PA-28-161, WARRIOR III
MAINTENANCE MANUAL
PAGE 6
Nov 30/06
5C12
74-10-00
(d) Inspect impulse coupling pawl latching
ends (see Figure 4). If rounded,
peened, or excessively worn, replace
impulse coupling.
NOTE: Str ingers, inclusions, and
heat checks may appear on
the surfaces of impulse
coupling components. These
conditions are normal and, by
themselves, generally do not
require impulse coupling
replacement.
(e) Inspect pawl retaining rivets. If loose
or, if they show indications of
movement, replace impulse coupling.
(f) Measure the clearance between the
boss on the underside of each impulse
pawl and the pawl plate using a feeler
gauge. Position the latching end of the
impulse pawl over the pawl plate as
shown in Figure 4.
(g) Maximum clearance for pawls with one
boss is .150 inch (see Figure 5).
Maximum clearance for pawls with two
bosses is .150 inch for left-hand
rotation couplings and .140 inch for
right-hand rotation couplings. If the
feeler gauge passes between the full
width of the boss(es) and the pawl
plate, replace the impulse coupling.
(4) In the left magnetos only (i.e. - impulse
coupled), reassemble and install the
impulse coupling:
(a) Lubricate the pawl assembly, hub and
spring with aircraft engine oil. Verify
that pawls move freely.
(b) Reassemble impulse coupling per
paragraph E (5), below.
(c) Inspect stop pin for looseness, cracks
or corrosion (see Figure 2). Replace
magneto frame, if found.
(d) Inspect stop pin for flat spots. These
are a normal sign of wear and do not,
of themselves, mandate component
replacement. However, if the flat spots allow the impulse coupling pawls to slip past the
stop pin, then either or both the impulse coupling and the magneto frame must be
replaced.
(e) Install impulse coupling per paragraph E (6), below.
Impulse Coupling
Figure 3
Impulse Coupling Pawls
Figure 4
Measuring Pawl Clearance
Figure 5