GMC 1976 ZEO 6083 Maintenance Manual page 349

2. Rough engine idle and stalling
5 . Engine to run uneven or surge
3 . Hesitation on acceleration
6. Poor fuel economy
4. Loss of power on acceleration and top speed
7. Excessive emissions
ENGINE FUEL SYSTEM
6M- 7
ENGINE CRANKS (TURNS OVER) WILL NOT START
OR STARTS HARD WHEN COLD
Possible Cause
Corrective Action
Improper starting procedure used .
Check with the customer to determine if proper
starting procedure is used, as outlined in the
operating manual .
No fuel in gas tank .
Add fuel . Check fuel gauge for proper operation.
Choke valve not closing suf-
Adjust the choke thermostatic coil .
ficiently when cold.
Choke valve or linkage binding
Realign the choke valve or linkage as necessary.
or sticking .
If caused by dirt and gum, clean with automatic
choke cleaner.
Do not oil choke linkage.
If parts are replaced, check adjustments.
Vacuum leaks in carburetor base
Check all manifold vacuum hoses for proper con-
or intake manifold .
nection and location . Check manifold and carburet-
or base gaskets for leaks. Tighten or replace as
necessary. Torque carburetor to manifold bolts to
15 ft . lbs.
No fuel in carburetor .
1 . Remove fuel line at carburetor. Connect hose to
fuel line and run into metal container. Remove
the high tension coil wire from center tower on
distributor cap and ground . Crank over engine - if
there is no fuel discharge from the fuel line,
check for kinked or bent lines . Disconnect fuel
line at tank and blow out with air hose, recon-
nect line and check again for fuel discharge. If
none, replace fuel pump . Check pump for adequate
flow .
2. If fuel supply is o.k . :
a. Inspect fuel filter . If plugged, replace.
b. If filter is o.k ., remove air horn and check
for a bind in the float mechanism or a sticking
float needle . If o.k., adjust float.