Triumph TR4A - Supplement: S.U. Carburettors; Carburettor Adjustments and Tuning

SUPPLE}IENT
S.U.
CARBURETTORS-TYPE
H.S.
Cold
Startinq
(Fies.
I
and
2)
Pulling
oit
the
choke
control
knob on the
instrument
Pan€l
operates
i le\er
to rotate the choke
bar
(l).
The movement
is
transferred
through
a cam
plate
(2)
lo
rotate the lhrottle
inler-
connecting
bar
(3)
and
open lhe throttles
beyond
the normal
idle
position.
iepending
upon lhe setting
of
rhe
screws
(6).
Simul-
ianeousty
the
jets-t5i
are lowered
by a link
rod. connecled
betweenihe
iet
head and the cam
plate
linlage.
to provide a
rich
mirrure
for'initial
cold slarting.
The accelirator'
pedal should
not
be depressed
when sta ing a cold engine.
Hot
Startine
Deoress-ihe
accelerator
pedal
to about
one third of
its travel
before operating
the starter switch.
Do not use the choke
control.
Acceleration
To
Drovide
for the requisite degree
of mixlure
enrichmenl.
at
the
mo'ment
of increased
throttl; opening
for acceleral.ion.
a
hydraulic
damper operates
in the
hollow. oil-filled
Piston
rod of
eich
carburetrbr.
The
piston rods should be
rePlenished
with
SAE
20 grade
engine oil at 6,000
mile intervals.
Float
Chamber
Fuel Level
(Fig.
3)
The fuel
level in the
float chamber
is
adjusted
by setting
the
float
lever on
the float chamber
lid, as follows:
l. Push
off the fuel
delivery piPe
from its connection and
remove the
float chamber
lid. Fie.
l.
(uppet)
Fie. 2.
(lower)
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