Saab 95 1967, Service Manual

Page: 182 / 610

DECELERATION
VALVE
1. Adjusting screw
2. Gasket
3. Spring
4. Valve
5. Body
6. Spring
7. Diaphragm
8. Bottom cover
9. Intermediate flange
Assembly is carried out in the reverse order.
Setting
Checking
NOTE
The air cleaner must be fitted.
1.
Run the engine until normal operating temperature.
2. Check that the deceleration valve is not working at
idling speed. This can be done by disconnecting one
of the hoses between carburetor and deceleration valve.
231—18
If the valve is open, Le. vacuum is passing the valve,
the adjusting screw on the deceleration valve has to
be screwed further in until the valve is closed. Can.
nect the hose.
If the deceleration valve is working at idling speed,
you will get a very fast idle (1 200—1 400 r/min). It
is not possible to adjust this in a normal way.
3. Connect a tachometer and adjust the idling speed in
accordance with the specifications in group O.
4. Advance the engine speed to 3 000 r/min with the
throttle. Let down the throttle rapidly and measure
the time as require to drop the engine speed from
3 000 r/min to idle.
An engine fitted with a correctly adjusted decelera-
tion valve should drop from 3 000 r/min to idle in
4 to 6 seconds. (USA-version as from model 1970
7 to 8 seconds.)
Adjustment
1. Remove the air cleaner.
2. a. If the requisite time from 3 000 r/min to 900 r/min
is more than the prescribed, the deceleration valve
adjusting screw should be screwed clockwise until
the desired figure is reached.
b. If the requisite time is less than the prescribed, the
adjusting screw should be screwed anti-clockwise
until the desired figure is reached.
ADJUSTING THE
DECELERATION VALVE
3. Fit the air cleaner and check the requisite time again.
If necessary, repeat the procedure until the requiSite
time is correct.
Failure of the diaphragm will allow air to pass from the
bleed hole in the cover, through the diaphragm and
straight into the inlet manifold. Normal adjustment of
idling speed is not possible. Replace the diaphragm if
combustion exhaust emission control is demanded. If
not, just cover up the bleed hole in the cover.
Fobr 1977