Chevrolet 10 Series 1970, Руководство по обслуживанию

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ENGINE FUEL 6M -9
NOTE: Vacuum and fr e e operation a re two
keys to c o r r e c t operation o f the R och ester g o v ­
ern or. If a ll parts are fr e e to m ove as intended
and there a re no vacuum leaks, the unit w ill
operate c o rre c tly .
G overning system s g en era lly malfunction in one of two
ways:
1. They do not govern at a ll. This could resu lt from :
a. A vacuum leak in the units o r tubing.
b. “ Spinner” unit stuck due to d irt, o il, o r some
other m a te ria l depositing in the m echanism .
c. O r ific e s in the ca rb u retor cloggin g so no vacuum
could be developed in the governing system .
2. The system “ o v e r g o v e rn s ” : govern s when it should
not, causes lo ss o f pow er, etc. This could resu lt i f
the vacuum passages w ere to becom e clogged with
d irt, o il, o r other fo re ig n m a teria ls. A re a s m ost
lik e ly to “ c lo g ” are the o r ific e s in the actuator, and
the a rea w here a ir bleeds through the distribu tor
“ sp in n er” va lve.
E ith er type o f malfunctioning could be caused by:
im p ro p e r spinner setting; spring post out o f position in
the carb u retor actuator; bent o r stretched spring in
actuator.
SUGGESTED PROCEDURE FOR F IN D IN G
CAUSES OF IMPROPER G O V E R N IN G
1. L o c a liz e the trouble on the veh icle. With the vacuum
tube disconnected at the distribu tor, run the engine at
about 3,000 rpm and place a fin g e r o v e r the end of
the tube. If there is no noticeable change in engine
operation, the trouble is probably in the actuator o r
tubing. If the engine speed is noticeably a ffected by
this, the distribu tor “ spin n er” can be suspected.
2. If d istrib u tor trouble is indicated p e rfo rm the fo llo w ­
ing operation (r e fe r “ Ignition System, S ervicin g units
o ff the V e h ic le ” in Section 6Y fo r detailed operation).
a. Rem ove distribu tor from engine, rem ove spinner
va lve and clean and visu ally inspect the p arts and
passages fo r p ossib le faults.
b. Check the seals. Do this by connecting the lo w e r
vacuum connector to a vacuum pump, and “ plu g­
g in g” the va lve hole in the shaft eith er with the
fin g ers o r other suitable means. Slight “ seep a ge”
around the seals is not abnorm al; how ever, a v a c ­
uum gauge reading within 2" hg. o f the maximum
that can be obtained w i t h the vacuum hose
“ squ eezed ” should be possible if the seals are in
s a tisfa cto ry condition. If the seals leak e x c e s ­
s iv e ly they should be replaced.
c. When the spinner parts are reassem bled, they
should be wiped with a rag saturated with light o il
to p ro vid e slight, but not e x c e s s iv e lubrication.
3. If actuator o r tubing trouble is indicated:
a. Rem ove the vacuum tube at the actuator, run the
engine at about 3000 rpm and place a fin g e r o v e r
the end o f the actuator. If there is no change in
engine operation, probably the actuator is at fault.
A sign ifican t change in engine rpm would indicate
tube leakage and tube should be replaced.
b. If the tubing is not d efective, check the actuator
fo r leakage. With the o r ific e s “ stopped up” with
the fin g e rs , o r other means, no leakage should
occur. A ls o check fo r p ro p er seal o f diaphragm
c o v e r and condition o f diaphragm its e lf. Vacuum
in the g o vern o r housing can be checked by r e ­
m oving the connection to the distribu tor and a t­
taching a vacuum lin e. If there is no vacuum
reading check the diaphragm fo r holes and be
sure the vacuum passage is cle a r.
c. If no leakage is found, clean a ll of the component
parts.
d. If tam pering is suspected, visu a lly check parts
with the govern in g parts o f an engine that is g o v ­
erning p ro p e rly .
AIR CLEANERS
INDEX
Page Page
General D e s c rip tio n .............................................................................. 6M-9 Inspecting Paper E le m e n t ................................................................ 6M-10
Maintenance Procedures ..................................................................... 6M-10 Cleaning Polyurethane B a n d ............................................................ 6M-10
Elem ent Replacement ..................................................................... 6M-10 Cleaning Oil Bath C le a n e r................................................................ 6M-11
GENERAL DESCRIPTION
A ir clean ers on a ll m odels operate p r im a r ily to r e ­
m ove dust and d irt fro m a ir b e fo re it is drawn into the
ca rb u retor and engine. The a ir clean er also helps to
reduce engine noise and quenches any flam e that may be
caused by engine b a ck fire through the carburetor.
T h ree types o f a ir clean ers a re used on trucks. They
a re the o il wetted paper elem ent a ir clean er, the two
elem ent a ir clean er and the o il bath a ir cleaner.
The o il wetted paper elem ent a ir clean er (fig . 1A) con­
sis ts o f an accordian pleated o iled paper filt e r supported
by w ire mesh with a p la s tis o l seal on both top and bottom.
The two elem ent a ir clean er (fig . 2A) consists of an o il
wetted polyurethane band wrapped around an o il wetted
paper elem ent.
The o il bath a ir clean er (fig . 3A) u tilize s an o il sump
in the a ir clean er bottom and a fib re elem ent.
On m ost applications o f the two elem ent a ir clea n er it
is used in conjunction with an exhaust m anifold heat stove
(fig . 4A). A ir tem perature is autom atically con trolled by
a therm ostatic v a lv e which se le cts warm ed a ir fro m the
CHEVROLET TRUCK SERVICE MANUAL