Buick LeSabre 1965 Service Manual page 95

ENGINE FUEL AND EXHAUST SYSTEMS
ADJUSTMENTS 3 - 1 9
SECTION 3-C
ADJUSTMENTS AND REPLACEMENTS-EXCEPT IN PUMP
AND CARBURETOR ASSEMBLIES
CONTENTS OF SECTION 3-C
Subject Page
3-7
3-8
Air Cleaner, Fuel Filter,
Manifold Valve and Ventilator
Valve Service 3-19
Carburetor Idle and Automatic
Choke Adjustments 3-21
Paragraph
3-9
3-10
Subject Page
Throttle Linkage and Dash Pot
Adjustments 3-25
Replacement of Gas Tank or
Gas Gauge Tank Unit 3-26
3 - 7 AIR CLEANER, FUEL
FILTER, MANIFOLD
VALVE AND
VENTILATOR VALVE
SERVICE
a. Air Cleaner Service
An air cleaner with a dirty ele-
ment will restrict the air flow to
the carburetor and cause a rich
mixture at all speeds. The device
will not properly remove dirt
from the air and the dirt entering
the engine will cause abnormal
formation of carbon, sticking
valves, and wear of piston rings
and cylinder bores.
Regular cleaning and inspection
of the element at 12000 mile in-
tervals (or more frequently in
dusty territory) is necessary to
prevent excessive engine wear
and abnormal fuel consumption.
The procedure for cleaning the
air cleaner is given in paragraph
1-1.
b. Cleaning Fuel Filter
The fuel filter is a can-type
throw-away filter and is located
in the line between the fuel pump
and the carburetor.
The filter element has a large
filtering area. It is of fine enough
material to assure that any parti-
cles which pass through it are
too small to interfere with the
operation of the float needle and
seat, and also too small to cause
clogging of the smallest passages
STANDARD FILTER
AIR CONDITIONER FILTER
VAPOR
BY-PASS
1
Figure 3-12—Can-Type Throw-Away
Fuel Filters
in the carburetor. This filter
prevents the passage of water
under ordinary conditions. The
filter should be replaced every
24000 miles for maximum filter-
ing efficiency. See paragraph 1-1.
After assembling the fuel filter,
always start the engine and ob-
serve the filter carefully to make
sure that the clamps are not
leaking.
A woven plastic filter is located
on the lower end of the fuel pickup
pipe in the gas tank. This filter
prevents dirt from entering the
fuel line and also stops water un-
less the filter becomes completely
submerged in water. This filter
is self cleaning and normally re-
quires no maintenance. Fuel stop-
page at this point indicates that
the gas tank contains an abnormal
amount of sediment or water; the
tank should therefore be removed
and thoroughly cleaned.
c. Cleaning Carburetor
Gasoline Strainers
Fine mesh strainers are located
in some carburetors above each
needle and seat. These strainers
should seldom require cleaning
because of the fuel filter which
precedes them in the supply line.
They should be inspected how-
ever, if fuel supply at carburetor
inlet is adequate but carburetor
operation indicates lack of fuel.
d. Freeing Up Sticking
Exhaust Manifold Valve
Lubricate the exhaust manifold
flange shaft every 6000 miles
(par. 1-1).
Carbon or l e a d salt deposits
around the valve shaft may cause
the valve to stick or become slug-
gish in operation. A valve stick-
ing in the open position will cause
slow engine warm up, excessive
spitting and sluggish engine op-
eration when cold. A valve stick-
ing in the closed position \vill
cause overheating, loss of power,
and hard starting when the engine
is hot, and may also cause warped
or cracked manifolds. Sticking in
either position will adversely af-
fect fuel economy.
If the manifold heat control valve
is sticking or seized in the flange
assembly, free it up by applying
a good solvent such as "Buick
Heat Trap Lubricant" to the valve