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The needle jet D screws horizontally into the
mixing chamber E, a.nd the main jet F is inserted
Írom undemeath.
Fig. ]4.
Amal carburetter.
Sliding, in and out of the needle jet as the throttle
is moved is the jet lieedle G, which, being, tapered,
varies the effective jet size in accordance with the
throttle position, thus ensuring correct mixture
strength at all times.
It will be seen tha,t the jet
needle is located ín the throttle slide by means of a
special spring clip engaging in one of the notches
at its outer end.
If the clip is moved to another
notch it will affcct the mixture streligth, a notch
32
nearer the end giving a weaker mixture, and a
notch in the other directioi) (f.e. nea,rer the ta.pered
shank) giving a richer mixture.
The float H maintains the correct level of petrol
in the floa.t chamber /, whose covei. K, held by
two screws, incorpora.tes a ga.uze filter £.
Attached to the top of the mixing chamber is
stub níf, also held by two screws, and this canies
the combined flame trap and air filter N.
Petrol Fllter.
The ga.uze petrol filter £ should be inspected a.nd
cleaned ií necessary at regular intervals, and this
can conveniently be done every time the engine is
decarbonised as described on pages 23 to 29.
Air Filter.
This is built into the carburetter intake bell and,
as it is of the oil dip type, it requires to be dis-
ma,ntled and cleanedperiodically, saiy, everythousaind
miles
To do this, relea,se the clip bolt, and take
the bell off.
Soq,k it thoroughly in petrol, allow it
to dry. a.nd then submerge it in light engine oil £or
a. Íew minutes.
Take out a,nd a,llow the surplus oil
to draili ofr.
Float Chamber.
AÍter very considerable mileages a small a,mour]t
of íoreign matter ma.y accumulate in the bottom
of the float chamber /, and if the cycle is used
during all weathers there ma,y also be one or two
beads of wa.ter.
The floa.t cha.mber ca,n easily be
cleaned out with a, I)iece oí dry rag, and when the
float is subsequently replaced make sure it is the
right way round, with the taper point oí the needle
upwards.
33
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