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10-42
CRANKING SYSTEM
ELECTRICAL SYSTEMS
(318)
cap. CAUTION: Do not use ordinary lubricants
as poor switch contact will be obtained in cold
weather. Do not apply lubricant to the ball or
plunger.
8. Place plunger in position with the groove
up so that the ball rests on lip at inner end of
plunger. See figure 10-40.
If
the plunger is in-
stalled with groove down, as shown in figure.
10-41, the ball will be prevented from rising
into the ball passage when the engine starts.
As a result, the switch will close each time the
throttle is opened, causing gear clash at low
speeds when the generator is not producing
sufficient voltage to open the solenoid relay.
If
generator should be inoperative, gear clashing
would occur at all speeds.
9. Make sure that all timing washers, con-
tact spring, and the return spring washer are
in proper position before installing the return
spring and terminal cap. Make sure that ter-
minal cap is properly seated. See figure 10-40.
10. After switch is assembled, check the
timing as described above (subpar. b or c), and
change shims as required until proper timing
is obtained.
10-33 ACCELERATOR VACUUM SWITCH
- ON STROMBERG CARBURETOR
a. Description and Operation
The accelerator vacuum switch used on
Stromberg
carbureto'rs
is
mounted
on the
throttle body of the carburetor by two screws.
A gasket placed between the switch housing
and the throttle body seals against loss of
vacuum.
The switch housing is provided with a hori-
zontal cylinder barrel to which vacuum from
Figure 10-41-Carter Accelerator Vacuum Switch
Incorrectly Assembled
the engine manifold is applied at one end by
means of cored and drilled passages in the car-
buretor bodies. This end of the barrel is pro-
vided with a washer which forms a seal to pre-
vent leaks when a piston opposed by a light
spring is drawn against it by vacuum. The op-
posite end of the barrel is vented to outside air
through a fine mesh screen which is held in
place by a screen clip. A flat slide, actuated by
an operating lever on the throttle shaft, moves
in a confined slot in the housing and in a plane
perpendicular to the axis of the cylinder barrel.
This slide engages a cylindrical bakelite con-
tact guide, the upward movement of which is
opposed by a heavy contact guide spring. The
contact guide carries a thin U-shaped spring
contact which moves up and down within a
bakelite terminal cap to engage stationary
contacts for opening and closing the cranking
motor control circuit. The terminal cap is held
in place by a cap screw and cap clip. See figure
10-42.
Figure 10-42 shows the accelerator vacuum
)I
~~'-WASHER
SCREEN CLIP
SCREEN
SLIDE
VACUUM PISTON
VACUUM PISTON SPRING
(THE LIGHTER SPRING
l
OPERATING LEVER
CONTACT
DIMENSIONS
CONTACT GUIDE SPRING
CAP SCREW
( T HE HEAVI E R
SPRING~~."illt~
CAP CLIP
/SPRING CONTACT
STATIONARY
¥
CONTACT GUIDE
Tl~~~~I
.....- . . . . , , - - . . ,
TERMINAL CAP
CLIP
SEAL
TERMINAL
HOUSING GASKET
SCREW
VACUUM CHANNEL
M~g~~~G
HOUSING
Figure 10-42-Stromberg Accelerator Vacuum Switch-Engine Not Running
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