Sunbeam ALPINE I SERIES: APLINE II SERIES, Workshop Manual

Page: 99 / 413

WSM.124
Section C (Fuel System)
can open against a light spring, even when the
choke control is still pulled out.
When the engine starts, with the choke valve
closed, air pressure acts on the larger pivoted area
of the choke butterfly valve, opening It a small
amount against its light control spring and the
lower pressure in the carburettor intake.
This allows entry of sufficient air to prevent over­
choking of the engine when starting from cold.
The carburettor strangler mechanism and various
positions taken by the cam lever are shown in Fig. 8
and the carburettor action when starting, in Fig. 7.
INTERCONNECTING ROD
(THROTTLE TO STAANGLER)
STR-'NGLEP.
V-'LVE
Page 13
Slow running (See Fig. 9)
With the throttle in the idling position, the mixture
is supplied by the idle jet which draws fuel through
the crossholes at the lower end of the main dis­
charge jet. This fuel, which is metered by the small
calibrated hole in the bottom of the idle tube, is
partly emulsified by air drawn from the air intake
through the air bleed hole and the mixture then
passes along an Internal channel to the idling orifice.
Idling is adjusted by means of the throttle stop
screw and the volume control screw (See Fig. 9). If
screwed In, the throttle screw will open the throttle
ST-'RTING FROM
COLO
FAST IDLING
NOP.MAL RUNNING
Fl1, 8. Strang/er
cam
positions