assemble. Throughly clean and inspect eachpart, NOTE using the procedure laid down in this Service Man
ual. The accompanying trouble shooting chart lists Many performance complaints attributed to
specific carburetor complaints and discusses the the carburetor may be the result of poor
various parts which may be at fault. A rigorous driving habits. It will be impossible to ob
cleaning and inspection, coupled withthe replace- tain fuel economy if the engine is needlessly
ment of faulty parts and care in reassembly, should raced, or if the throttle is abused with harsh
prevent recurrence of the complaint, sudden openings.
TROUBLE SHOOTING CHART
|
DIAGNOSIS |
POSSIBLE CAUSE |
CORRECTION |
|
Rough running engine from over- |
Excessive choking. |
Check choke linkage for binding |
|
rich mixture on starts and warm- |
or damage. Check thermostat | |
|
up. Black exhaust, fouled plugs, |
setting. (Must be within two marks | |
|
poor economy may result. |
of center index). Check condition | |
|
of fresh air tube from carburetor. | ||
|
With engine idling, check for air | ||
|
leaks between choke housing and | ||
|
manifold. Be sure choke housing | ||
|
is mounted tightly to manifold. | ||
|
Use new gasket when installing | ||
|
choke. | ||
|
Sluggish rough running engine on |
Insufficient choking. |
Check for all of above items. |
|
cold starts. Stalling, back-firing |
Also check for damaged or dis | |
|
into carburetor may result. |
torted thermostat spring fusing | |
|
an automatic choke. | ||
|
Stalling when accelerator is sud- |
Improperly set or defective dash- |
Check dashpot response by |
|
denly depressed and released. |
pot. |
depressing dashpot rod and |
|
(Automatic transmission and/or |
releasing suddenly. A definite | |
|
power brake equipped vehicles |
resistance should be felt when | |
|
only.) |
the rod is depressed, but it | |
|
should snap back immediately | ||
|
when it is released. Be sure | ||
|
dashpot adjusting screw is set | ||
|
to specification. |
or
COMPLAINT: Rough Idle
May be particularly noticeable following seasonal weather changes. Turn needle(s) off present setting in both directions and check for increases in rpm.
Idle adjusting needle(s) improperly set.
Readjust both idle adjusting needles as outlined in "Adjustments" section of this manual. Be sure thatidle adjusting needle springs are tight.
Impossible or extremely difficult to set idle mixture correctly. Remove idle adjusting needles and inspect tips.
Damaged tip on idle adjusting needle(s).
Replace damaged needle(s) with authorized Holley replacement parts. Adjust as outlined in "Adjustments" section of this manual.
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