Chevrolet 10 Series 1968, Service Manual

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ENGINE 6-6
FLAME ARRESTOR
FLAME ARRESTOR
NON-VENTED
CAP
VALVE
VALVE
FLAME ARRESTOR
NON-VENTED CAP NON-VENTED CAP
CLOSED POSITIVE IN LINE (TYPICAL) CLOSED POSITIVE V8 (TYPICAL)
CLOSED POSITIVE V8 (366)
F 'g
2. Push hand choke knob in to within 1/8" of instrument
panel.
3. Loosen choke cable at carburetor bracket and adjust
cable through the clip until the choke valve is wide
open.
Tighten cable clamp at carburetor bracket and check
operation of choke valve to ensure full closed and
wide open positions.
INSTRUMENT CHECK-OUT
10—Crankcase Ventilation Systems
4.
Instrument Hook Up
Connect vacuum gauge, dwell meter, tachometer and
timing light as recommended by the manufacturer of the
equipment being used.
Check and Adjust Dwell
1. Start engine then check ignition dwell.
2. If dwell is not within specifications, adjust dwell as
follows:
V8 ENGINES
• With engine running at idle, raise the adjustment
screw window and insert an Allen wrench in the
socket of the adjusting screw (fig. 11).
• Turn the adjusting screw as required until a dwell
reading of 30° is obtained. A 2° variation is allow­
able for wear.
• Close access cover fully to prevent the entry of
dirt into the distributor.
WINDOW
"HEX” TYPE
WRENCH
SCREW
F ig . 11—Setting Point Dwell (T yp ica l V8)
NOTE: If a dwell meter is not available, turn
adjusting screw clockwise until engine starts to
misfire, then turn screw one-half turn in the
opposite direction to complete adjustment.
IN LINE ENGINES
• Remove distributor cap and recheck point setting.
If dwell is still not within specifications check the
distributor as outlined in Section 6Y.
Check Dwell Variation
Slowly accelerate engine to 1500 rpm and note dwell
reading. Return engine to idle and note dwell reading.
If dwell variation exceeds specifications, check for worn
distributor shaft, worn distributor shaft bushing or loose
breaker plate.
Check and Adjust Ignition Timing (Fig. 12)
1. Disconnect the distributor spark advance hose and
plug the vacuum source opening.
CHEVROLET TRUCK SERVICE MANUAL