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18
FIAT· 850 PASSENGER CARS
Engine Misses While Idling.
POSSIBLE
CAUSES
1) Spark plugs dirty, damp or the gaps set too wide.
2) Broken or loose ignition wires.
3) Burned or piUed breaker contact points, or set
with insufficient gap.
4) Coil or condenser defective.
5) Distributor cap cracked.
6) Distributor rotor contact worn.
7)
Excessive play In distributor shaft or shaft cam
worn.
8) Burned, warped or pitted valve•.
9) Incorrect valve tappet clearance.
10) Incorrect <:arburetor idle adjustment.
11) Incorrect fuel level in carburetor.
12) Poor compression.
Crankshaft Knocks.
REMEDIES
1) Clean spark plugs and adjust gap as recommended under
It
Spark Plugs
».
2) Check wiring cables for secure fastening to terminals and
spark plug inserts.
3) Overhaul and adjust contact points as recommended under
«Ignition Distributor
».
4) Bench test coli and condenser and replace them,
if
required.
5) Replace cap.
6) Replace distributor rotor.
7) Rebuild ignition distributor and replace worn parts.
8) Overhaul cylinder head and replace valves. Proceed u
recommended under
«
Cylinder Head
If.
9) AdJust clearance as recommended under «Valve Mech-
anism
».
10) Adjust idle speed as recommended under «Carburetor
If.
11) Check and adjust float level as recommended under
«
Car-
buretor
».
12) Check compression using a pressure gauge:
If
pressure
is too low, locate causes and remove them.
These knocks are usually detected as metallic, heavy and dull knocks which increase in frequency
with the engine speed. Excessive crankshaft end play (shoulder play) causes a sharper. drier noise which
occurs at irregular intervals.
POSSIBLE
CAUSES
t)
Excessive clearance between main bearings and
journals.
2) Excessive end play.
REMEDIES
1) Remove crankshaft, check Journals and bearing condition;
grind crankshaft and replace bearings as outlined under
«
Crankshaft».
2)
Cheek end play and ule oversize thrust rings,
If
necessary.
(CI:ltltlnued)
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