Chevrolet 10 Series 1970, Service Manual

Page: 365 / 671

SECTION 6 M
ENGINE FUEL
CONTENTS OF THIS SECTION
Page Page
Carburetors
Governors .
A ir Cleaners
6M-1 Fuel P u m p s ........................................................................................... 6M-14
6
M-6 Special T o o l s ......................................................................................... 6M-19
6M-9
CARBURETORS
INDEX
Page Page
General D e s c rip tio n ............................................................ ...............
6M-1 Carburetor R e m o va l................................................. .................... 6M-4
Service P ro c ed u res .............................................................. ................
6M-1
Carubretor Test Before In sta lla tio n ...................... .................... 6M-4
Preliminary C h e c k s .......................................................... ...............
6M-1 Carburetor Installation .......................................... .................... 6M-4
Fast Idle Adjustment ..................................................... ............... 6M-1 Fuel F ilter Maintenance ........................................ .................... 6M-4
Float Adjustment ( H o l l e y ) ............................................. ...............
6M-2 A u tom atic Choke C oil A sse m b lies........................ ....................
6M-5
Vacuum Break Adjustment .......................................... ...............
6M-3 Choke C oil R e p la c e m e n t........................................ ....................
6M-5
T h rottle Return Check Valve Adjustm ent ..................
........... 6M-3 Idle S o le n o id ............................................................ .................... 6M-5
A dd ition a l A d ju s tm e n ts .................................................
6M-3 T h ro ttle Linkage Adjustm ent ............................... .................... 6M-6
GENERAL DESCRIPTION
V ariou s ca rb u retors, designed to m eet the p a rticu lar
requ irem en ts of engine, tran sm ission and veh icle are
used; th erefo re, ca rb u retors that look alike are not a l­
ways interchangeable. (R e fe r to ca rb u retor part number
and/or sp ecifica tion s.) C a rb u retors fo r engines with the
A ir Injection R eactor System are designed, p a rticu la rly
fo r these engines; th e re fo re , they should not be in te r­
changed with o r rep laced by a carb u retor designed fo r an
engine without the A ir Injection R ea ctor System.
This Section c o v e rs rem ova l, installation and adjust­
ment (on engine) o f ca rb u retors. A lso c o vered in this
section a re maintenance p rocedu res fo r throttle linkages
and fuel filte r s . F o r ca rb u retor overhaul procedu res and
additional adjustments (bench), r e fe r to Section 6M of
the Overhaul Manual under the carbu retor being s e rv ic e d .
Specifications fo r ca rb u retors are located in the back
o f this manual.
SERVICE PROCEDURES
Prelim inary Checks
1. Thoroughly w arm -up engine. If the engine is cold,
allow to run fo r at lea st 15 minutes.
2. Inspect torque o f ca rb u reto r to intake manifold bolts
and intake m anifold to cylin d er head bolts to exclude
the p o s s ib ility of a ir leaks.
3. Inspect m anifold heat con trol va lve ( i f used) fo r f r e e ­
dom o f action and c o r r e c t spring tension.
4. Check and adjust choke as requ ired, using p r o c e ­
dures sp ecified in "E n gin e T u n e-u p " section.
5. Adjust id le speed and id le m ixture as outlined in
“ Engine Tune-up” section.
Fast Idle Adjustm ent
Rochester M V , 4 M V and H olley
NOTE: The fast id le adjustment must be set
with e le c tr ic a l leads to the T ran sm ission Con­
tro lled Spark (T C S ) solenoid disconnected (fig .
l c ) and tran sm ission in “ N eu tra l” .
1. P osition fast id le le v e r on high step o f fast idle
cam . (Second step on 4MV)
2. Make sure choke is p ro p e rly adjusted and in wide
open position - engine w arm .
F ig . l c —Transm ission C o n tro lle d Spark E le c tric a l Lead
I TCS S O LE N O ID
ELECTRICAL LEAD
CHEVROLET TRUCK SERVICE MANUAL