Chevrolet 10 Series 1968, Service Manual

Page: 403 / 713

ENGINE FUEL 6M-10
engine operation, probably the actuator is at fault.
A significant change in engine rpm would indicate
tube leakage and tube should be replaced,
b. If the tubing is alright, check the actuator unit for
leakage. With the orifices "stopped up" with the
fingers, or other means, no leakage should occur.
Also check for proper seal of diaphragm cover
and condition of diaphragm itself. Vacuum in the
governor housing can be checked by removing the
connection to the distributor and attaching a vac­
uum line. If there is no vacuum reading check
the diaphragm for holes and be sure the vacuum
passage is clear.
c. If no leakage is found, clean all of the component
parts.
d. If tampering is suspected, visually check parts
with the governing parts of an engine that is gov­
erning properly.
AIR CLEANERS
INDEX
Page Page
General D e s c rip tio n ................ ............................................ 6M-10 Cleaning Paper E le m e n t ................................................ 6M-11
Maintenance P r o c e d u r e s ................................................... 6M-11 Cleaning Polyurethane B a n d ..........................................6M-11
Element R e p la c e m e n t................................................... 6M-11 Cleaning Oil Bath C le a n e r ............................................. 6M-12
GENERAL DESCRIPTION
A ir cleaners on all models operate primarily to re­
move dust and dirt from air before it is drawn into the
carburetor and engine. The air cleaner also helps to
reduce engine noise and quenches any flame that may be
caused by engine backfire through the carburetor.
Three types of air cleaners are used on 1968 Chevrolet
trucks. They are the oil wetted paper element air
cleaner, the two element air cleaner and the oil bath air
cleaner.
The oil wetted paper element air cleaner (fig. 1A) con­
sists of an accordian pleated oiled paper filter supported
by wire mesh with a plastisol seal on both top and bottom.
The two element air cleaner (fig. 2A) consists of an oil
wetted polyurethane band wrapped around an oil wetted
paper element.
The oil bath air cleaner (fig. 3A) utilizes an oil sump
in the air cleaner bottom and a fibre element.
On most applications of the two element air cleaner it
is used in conjunction with an exhaust manifold heat stove
(fig. 4A). A ir temperature is automatically controlled by
a thermostatic valve which selects warmed air from the
heat stove and/or cooler air from the engine compart­
ment or from outside the vehicle.
Diesel engine applications require the use of several
types of oil bath air cleaners. All types are serviced in
a manner similar to the gasoline engine oil bath air
cleaners.
BOTTOM
ELEMENT
COVER
F ig . 1A - Paper Element A ir Cleaner
F ig . 2A - Two Element A ir Cleaner
CHEVROLET TRUCK SERVICE MANUAL