Piper PA-24 Comanche Service Manual page 381

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PIPER COMANCHE SERVICE MANUAL
;. Turn the crankshaft very slowlyin diree:tion of normal rotation until the riming mark on the front
hce of the 0111 par w,ns with the clrilled bole in the starter or the timing mark on ehe baa of the rins
gear
~igns
with the aankcase putinf sunac:es. At this pOint the liBht should
10
OUt.
k. If the iight does not
go out at this point. a1ip
tirDinJ
marits and rotate magneto on mounnnc
nan,e in me desired direction and repeat the procedure until the litht IOcs out at _25 dqrees before tOP
dead center.
CAUTION
When timiftl rcurd breaker mqnetOI to the enpne. only main breaker
points
ate
timed. Never mempc
to
time retard brc&kct points to the
engine.
Install nuness plate and secure with screws.
Connect "P" leads and safety.
Connect starring vibrator lead to the left ·200 mqnetos.
Secure engme cowling. u,
s,
t.
L Tighten the two mowarinl nun and replac:e the inspection plut.
m. After tighteniftl mqneto mOllntiq nua. check timin, to make sure it is still correct.
n.
Install the other mqneto and time uu, the preced"" inmuctiQnl A through M.
O.
With both macnetos timed to the engine and
secured,
check that they fire together. Rotate the
crankshaft 0ppoSlte normal rotation to apprOximately 35 dcgrca BTC with So. 1 cylinder on the
compression stroke.
p.
If tbe mqnccos are timed correctly, both timin,
liJha
will
go out simultaneously when the
crankshaft is tumcd in the nonnal direcaon &ligninl the 2' dqree marks with the drilled hole in the starter
housoftJ or the crankcase puring surfaces.
q. Disconnect tinung litht. Ascenain that the inspection plugs aDd breaker cover are inStaned and
secure.
r.
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7A-;4.. SW"Cin1 VibratOr Checkin, Procedure.
a. ."1easure voltate berween vibrator terminal marked "in" and the ground terminal wiule operating
starter. Output must be a.t lcut a-volu on 12·volt systems.
b. If VOltage is adequate. listtn for buum, of vibrator durin, sta.nin,. If no buzzing is heard. eIther
the vibrator is defective or the cirC\l.it from the outpUt "BO" terminI! on the vibrator to the retard tdual
breaker) magneto is open. Check both switch and retard Circuits. Also check for good electrical Il'0und.
c. Retard potnu may not be dOlin, due to \\TO"I adjustment. or may not be electrically connected
In the circuit due to
1
poor connection. Inspeer retard points to see if they close. Check for ?roper .:onract
at
the swltch 1nd retard terminals of retard (dual breaker) mqneto. and at the vibrator. Check wiring.
d. Turn engine in proper direction of rotatioo until retard points JUSt open on
:"010.
one cylinder
posuicn, Remove input connection from starter to prevent enpe turning. Hold So. one plug head 5116
Inch from ground; energize \"'ibrator by tumlftg switch to
SCart.
P1ur
lea.d should throw a 5116 inch spark.
Observe sparx
at
plup spark cap. If spark is weak. or missing, tty new vibrator. If this does not correct
trouble. remove militleto and check for improper internal timing or improperly meshed distributer ge1r5.
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POWER PLANT
ISSUED: 8/18/72
2
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