Chevrolet Corvette 1963 Repair & Tune-Up Manual page 173

omy by tampering with emission controls is
more likely to worsen fuel economy than im-
prove it. Emission control-changes oh modern
engines are not readily reversible. 16. Clean
(or replace) the EGR valve and
23. Check for fuel leaks at the carburetor,
fuel pump, fuel lines and fuel tank. Be sure all
lines and connections are tight.
24. Periodically check the tightness ,of the
carburetor and intake manifold attaching nuts
and bolts. These are a common place for vac
uum leaks to occur.
25. Clean the carburetor periodically and lu
bricate the linkage.
26. The condition of the tailpipe can be an
excellent indicator of proper engine combus
tion. After a long drive at highway speeds, the
inside of the tailpipe should be a light grey in
color. Black or soot on the insides indicates an
overly rich mixture.
27. Check the fuel pump pressure. The fuel
pump may be supplying more fuel than the en
gine needs.
28. Use the proper grade of gasoline for your
engine. Don't try to compensate for knocking or
"pinging" by advancing the ignition timing. This
practice will only increase plug temperature
and the chances of detonation or pre-ignition
with relatively little performance gain.
42. Be sure the front end is correctly aligned.
A misaligned front end actually has wheels go
ing in differed directions. The increased drag
can reduce fuel economy by .3 mpg.
43. Correctly adjust the wheel bearings.
Wheel bearings that are adjusted too tight in
crease rolling resistance.
lines as recommended.
17. Besure that all vacuum lines and hoses
are reconnected properly after working under
the hood. An unconnected or misrouted vacuum
line can .wreak havoc with engine performance.
2° 4° 6°
TIMING OVER-ADVANCE (BTDC)
Increasing ignition timing past the specified setting
results in a drastic increase in spark plug tempera-
ture with Increased chance of detonation orpreigni-
tlon. Performance increase is considerably less.
(Photo courtesy Champion Spark Plug Co.)
Check tire pressures regularly with a reliable pocket
type gauge. Be sure to check the pressure on a cold
tire.
12
10
8° 10° 12°
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