Piper PA-24 Comanche Service Manual page 469

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PIPER COMANCHE SEFcVICE MANUAL
,. After !1UInC'tos have been properly timed. replace breaker covcrand secure.
h.
Install the P'OlInd lead and the
mard
spark
lead on the
left
mqncto.
i. Place the hamas tcnniaa.l plate on the mllfteto aad nptcn Illlt arollftd the plate a.ltcmately to
sat cover sqllarely on
mqueco.
Torque Illlts to 18 to
12
iAch pounds.
1C-'4.
Sanint Vibntor Cbeeldn,
Procedwe.
a. Measure voltap between
vib~tor
terminal
madtcd "in" and
the
pound
termiIW while opcratinl
saner. Olltpllt mllst be at leut 8-vola on 12-volt sysccms.
b. If volcqe
is aclcqIWe. listeD for bllZZiq of vibrator dwint
startinI.
If no buzzinl is hard, either
the vibrator is defective or the circuit from the output "10" terminal on the vibrator to the mud (dual
breaker)
lDapftO
is open. Check boch
switch and
mud circuia.
Also check for lood electrical JfOllad.
c. Retard poina may not be c.losiq due to
wroftl adjllltDlCDt. or may not be electrically COMected
in the circuit due to a poor connection. IASpec:c
rccard
poina
to
see if they close. Check for proper contact
at the switch aDd reuzd tcmWWs of
mud
(dua!
braker)
maenao aad at the vibrator. Check
' N irin,.
d.
Tum e"line in proper direction of rotation IlDcil retard poina just
open on No. one cylinder
position. Remove input coaaection from SQfter to prevent cnpae tumiq. Hold No. one plUl head '/16
inch from If'Ound eneqize vibrator by
tumiDI
switch
to
RUt.
Pl\lllad.should thl'OW a '/16 inch spark.
Observe spark at pilip spark cap. If spark is weak or minirll.
tty
new vibtator. If this does not COrtect
trollble. remove mlfDeto aDd check for improper intema!
cimini
or improperly meshed di.scrib,uor leatS.
CAUTION
When checki.. vibrator action. stand clear of propeller or mnove
spark
plllg terminalJ.
7C05'. HU'DCSI A.uembly.
7C·'6. Inapection Of H _ .
I.
Check lead UICIIlbUcs for nicks. cua. mutilucd braidiq. badly worn section or any other evidence
of physical damace. lllSf)CCt spark pllli sleeves for cbafUII or tears and damaged or stripped threads on
cOllplinl nuts. Check compression
sprina to see if it is broken or distorted. Inspect grommet for tears.
Check all mounnna bndteu aDd clamps to see that they are secure and ace cracked.
b.
lJsiDI
an ohmmeter. buzzer. or other suitable low voltap device, cbeck each lead for continuity. If
continuity does
nOt
exist. wile is broken and must be replaced.
c. Minor repair of the hamcss usembly. sllch u replacement of contact sprints. spring retainer
assemblies, insulating sleeves or of ODe lead assembly, can be accomplished with the harness allCmbly
mOllnted on the ftIpe. However. should repair reqllire replacement of more than one lead usembly or of
I
cable olldcc plate, the harness should be removed from the engine aad sent to an overhaul shop.
POWER PlANT
ISSUED: 8/18/72
2
H17