Sunbeam ALPINE I SERIES: APLINE II SERIES, Workshop Manual, Page: 100 / 413

Page 14
SUNBEAM
Section C (Fuel System)
wider and increase the engine speed and when
unscrewed the speed will be reduced.
The strength of the idling mixture is established by
the size of the idle jet and that of the air bleed.
The jet size is variable, but the air bleed is drilled
in the carburettor casting and is not Intended to be
altered.
The volume control screw which has a tapered tip,
and Is on the engine side of the throttle, controls
THE AMOUNT of idle mixture passed to the engine.
SLOW RUNNING
AIR BLEED HOLE
SLOW RUNNING
CHANNEL
MAIN DISCHARGE
JET
STRANGLER
(FULLY OPEN)
IDLING
ORIFICE
To weaken the mixture, the screw should be turned
clockwise; conversely it must be unscrewed to
make the mixture richer.
The two small holes at the throttle edge break
into the idle channel. These assist in the transfer
from the Idle system to the main metering system
as the throttle is opened, and provide a smooth and
progressive action during that period; they are
known as "progression holes", and are not adjust­
able. It is important that they are not tampered
SLOW RUNNING
VOLUME CONTROL
PROGRESSION
SCREW HOLES
- -
THROTTLE VALVE
ALMOST CLOSED
- - AIR FLOW
- FU_EL.
Fig. 9.
Idling operation conditions