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230
FIAT.850 PASSENGER CARS
drive pulley is at 9/16" to 19/32" (14 to 15 nun)
(engine lOOG.OOO) or 1/2" to 9/16" (13 to 14 nun)
(engine lOOG.OO2) ahead of the mark on timing
gear cover (fig. 358); this corresponds to the position
specified for the static advance before l.d.c.
Remove the distributor cap and rotate the drive
shaft with insert
by
hand until rotor points to contact
for
firing in
cylinder No. l.
In this
position contacts are about to snap open
(check first
if
maximum contact distance is .0165"
to .0189" - 0.42 to 0.48 nun).
Without disturbing distributor shaft, insert lower
coupling on its toothed end, install support and
tighten the lock screw on crankcase.
Ignition timing may be checked more easily
using tester Ap. 5030 (fig. 357) as follows.
Connect tester Ap. 5030 to a single-phase 220 Volt
power outlet, fined with grounding insert.
The
grounding of the tester must be made positively.
before or when plugging in the tester service cord.
Under no circumstances the tester must be operated
without grounding connection.
Connect ground terminal (5, fig. 357) with an
unpainted metal portion of car under test.
Set the cable (4) for strobe lamp (I) control be-
tween the spark plug No. I and its wire.
Fit graduated plate Ap. 5030/9 (fig. 357).
Chalk off the T.D.C. mark on generator drive
pulley.
Start the engine and aim the winking light beam
of tester (1) on the chalk mark drawn on pulley.
U
ignition is timed correctly, at idling speed the
mark on pulley must be aligned with the white line
(10 0 or 11 0) on plate Ap. 5030/9.
IGNITION SYSTEM TROUBLE DIAGNOSIS
Ignition Faulty or Completely Absent.
POSSIBLE
CAUSES
1} Condenser shorted or with low insulation resist-
ance.
2) Cap cracked or showing signs of carbon on Inner
face; moisture deposits.
3} Cracks, carbon or=molsture deposits on rotor.
4} Center brush worn or broken, brush spring de-
formed.
5} Build-up and pitting on points.
6) Points oxidized or blackened.
7) Excessive point gap.
REMEDIES
1} Low voltage in secondary circuit; poor sparking.
-
Renew condenser.
2) Current leakage to ground along cracks, burned paths or
moisture.
-
Remove moisture or carbon deposits.
-
Renew cap, If cracked.
3) Ground leakage as at 2).
-
Remove moisture or carbon deposits.
Recall that rotor
and/or cap must be renewed if their terminals are worn
more than .0118" (0.3 mm).
4} Arcing occurs between rotor and center brush causing cor-
rosion and oxidation. Spring distortion and brush breakage
can be detected by visual Inspection.
-
Renew cap.
5) Point gap lesser than specified.
-
Adjust point gap to .0165" to .0189" (0.42 to 0.48 mm).
Renew points,
If necessary, or camshaft If
N
worn.
6) High resistance In condenser circuit due to faulty connec-
tions or broken leads.
Contact faces oiled or soiled.
-
Remove oxidation, possibly.
-
Renew condenser, cap or brush, it necessary.
7) Weak sparking, especially at high speed.
-
Adjust point gap to .0165" to .0189" (0.42 to 0.48 mm), as
specified.
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