Chevrolet 10 Series 1970 Service Manual page 372

ENGINE FUEL 6M -8
F ig . 3 G — G o v e rn o r— Exploded V ie w
1. G o v e rn o r Housing
2. D iaphragm Assem bly
3. D iaphragm C o ve r
4. G o v e rn o r Lever
body w ere d rille d a fte r the throttle body was
assem bled, the throttle v a lv e s w ere nicked dur-
ing the d rillin g operation.
made to rem ove the throttle valve o r to further
disassem b le the throttle body, since any slight
change in positioning o f the throttle va lve s with
relation to the idle p orts would s e riou sly disrupt
ca rb u retor operation.
Cleaning and Inspection
The throttle le v e r and bearing assem bly should not be
im m ersed in any carb u retor clean er, since it might cause
dam age to the neophrene seal p rotecting the b all b e a r­
ings. If the throttle body it s e lf is im m ersed in solvent,
g rea t care must be taken that the throttle shaft bearings
a re blown com pletely dry with com p ressed a ir. They may
then be lu bricated with v e r y light machine o il. Since the
calibration o f vacuum versu s spring tension is o f extrem e
im portance in go vern or operation, it can rea d ily be seen
that th ere should be no e x ce s s iv e frictio n in throttle shaft
(2 G V A C U U M SPINNER TYPE)
1. L o s s o f speed control:
Check fo r vacuum leaks and operation o f bleed va lves
in distribu tor. A lso 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 go vern or housing can be checked by rem ovin g the
5. G o v e rn o r S pring
6. L e athe r Seal
7. Leather Seal R eta in er
8. G o v e rn o r C over
No attempt should be
TROUBLE SHOOTING
rotation. If e x cessive fric tio n is noted, the throttle body
assem bly must be replaced.
Instaliation
1. P osition the gasket ca refu lly on the throttle body and
assem ble the throttle le v e r and bearin g assem bly to
the throttle body with the four screw s provided. To
be certain that the throttle le v e r and throttle shaft
are in p rop er relation hold the throttle va lv e closed
while attaching the throttle le v e r assem bly. Position
the throttle le v e r during assem bly so that it fits
ea sily onto the throttle body. If this procedu re is
follow ed the assem bly
c o rre c tly .
2. P la ce the go vern o r housing to throttle body gasket in
place, noting that the n a rrow er edge goes toward the
top o f the carbu retor.
ov e r the gasket.
3. Slide the leath er seal and retain er o v e r the throttle
shaft, position the s crew holes in c o rr e c t relation
and install the housing
loosely.
4. Check the throttle shaft fo r fr e e rotation in the seal,
then tighten the housing screw s. The throttle va lves
must be held in a closed position while tightening the
screw s. Recheck fo r fr e e
sem bly procedu re i f n ecessary.
5. Install the diaphragm in the govern o r housing with
the end o f the diaphragm rod pointing inward. W ith
the diaphragm in this
vacuum passage in the diaphragm should line up with
the vacuum passage in the housing. A ssem b le the
govern or le v e r and pin assem bly to the diaphragm
rod and position the le v e r on the throttle
Install the nut and lockw asher, holding one o f the
throttle va lves between thumb and fo re fin g e r while
tightening, to avoid damage to the th rottle va lves.
6. Position the diaphragm ca refu lly o v e r the screw
holes in the housing.
c o v e r res trictio n pilots through the gasket and into
the vacuum passage in the body. Install the eight
screw s fin g e r tight. Open the throttle v a lv e s wide to
p rovide maximum tra v e l of the diaphragm and tighten
the eight c o v e r sc rew s to 25 to 28 inch pounds o f
torque while holding the diaphragm in this position.
Install lo c k w ire on
Install the go vern or spring o v e r the le v e r pin and the
stationary post in the housing.
7. Check again fo r fr e e operation of the throttle shafts,
then in stall the govern or, co ve r and four attaching
screw s, and in stall lo ck w ire (shown in F igu re 1G).
8. Attach the pump rod and fast id le cam to the throttle
le v e r assem bly.
9. Install vacuum tube to diaphragm c o v e r and d istribu ­
tor and install lock w ire in attaching nuts.
connection to the distribu tor and attaching a vacuum
line. If there is no vacuum reading check the dia­
phragm fo r holes and be sure the vacuum passage is
clea r.
2. E rra tic operation under load:
Check fo r e x ces siv e
throttle le v e r.
w ill operate fr e e ly
Then put the housing in place
to throttle body screw s
rotation and repat a s ­
position the hole fo r the
shaft.
Position the c o v e r so that
screw s (shown in Figu re
frictio n in throttle shaft and
CHEVROLET TRUCK SERVICE MANUAL
and
1).