SPARK PLUG WIRING REPLACEMENT.

check for cracks in the coil case. Check coil

e. After cleaning, examine the plug carefully for

terminals for tight connections and proper

cracked or broken insulator, badly eroded

polarity.

electrodes and other signs of failure. Replace as

required.

4-44. DISTRIBUTOR CHECKS. Disconnect spark

plug wiring at the distributor cap, remove

f. Clean the electrode surfaces with a small file.

distributor cap and make the following inspection:

Dress the electrodes to secure flat parallel surfaces

on both the center and Bide electrode.

a. Distributor Cap: Clean the distributor cap with

a soft bristle brush and Stoddard type cleaning

g. Adjust the spark plug gap to: Standard 0.025

solvent. Dry the cap with compressed air. Inspect

inch, Resistor 0.035, by bending only the outside

t h e cap for cracks burned contacts, permanent

electrode. Use a round wire-type gauge to check

carbon tracks or dirt or corrosion in the sockets.

the gap. If old spark plugs are reused, install with

Replace the cap if it is defective.

new gaskets. Torque to 35 pounds/feet.

b. Rotor: Clean the rotor with a soft bristle

Note

brush and a Stoddard type cleaning solvent. The

rotor should be dried with compressed air. Inspect

Do not overtighten spark plugs, the gap

the rotor for cracks or burning. Replace the rotor

may change considerably due to distortion

if it is defective.

of the plug outer shell, or the insulator may

be cracked.

c. Check the contact dwell. If the contact dwell

i s not within specifications, adjust the breaker

4-42. SPARK PLUG WIRING REPLACEMENT.

points.

Whenever an examination of the high tension

wiring reveals

cracks, c h a f e d a r e a s , b u r n e d

d . Check the breaker arm spring tension and

i n s u l a t i o n or other deterioration, the wiring set

adjust it if necessary.

should be replaced. Such poor insulation leads to

rapid spark plug fouling and misfiring due to

4-45. CENTRIFUGAL ADVANCE. The spark

current leakage.

a d v a n c e is checked to determine if the ignition

timing advances in proper relation to engine speed

When removing the wires from the spark plugs -

and load.

grasp, twist, and pull on the moulded cap only. Do

not pull on the wire because the wire connections

a . Connect the electrical leads of a distributor

inside the cap may become separated or the

t e s t set to the distributor. Do not connect the

weather seal may be damaged.

vacuum line to the diaphragm. Set the tester for 0

degree advance at 300 RPM.

Removal: Disconnect wires at plugs and at the

distributor cap. Remove coil high tension lead.

b . Operate the distributor in the direction of

Installation: Connect wires to proper plugs. Insert

rotation and slowly increase the RPM to the setting

ends of wires in the correct Sockets in distributor

specified for the first advance reading listed in the

cap. Be sure wires are all the way down into their

specifications.

sockets and that they are held firmly in position.

The No. 1 socket is identified on the cap. Install

c. If the correct advance is not indicated at this

wires in a clockwise direction in the firing order

R P M , stop the distributor and bend one spring

l-2-4-3, starting at No. 1 socket. NOW install coil

adjustment bracket to change its tension. Bend the

h i g h tension lead. Push all weather seals into

adjustment bracket away from the distributor shaft

position.

to decrease advance (increase spring tension) and

t o w a r d the shaft to increase advance (decrease

4-43. IGNITION COIL CHECKS. Check the coil

s p r i n g tension). After the adjustment is made,

for secure mounting. Wipe the coil with a damp

cloth moistened in Stoddard type solvent and

identify the bracket that is bent.

4-34