Begin OCR Text:
' _ 1 1
1 _ Fig_ 13_ C_rburettor function, normal runnin'g'. '
_''_ Blue = Atmospheric Red = Fuel
pressure Lighf red _ Fuel, air
Yellow= Vacuum mi__u_e
1 , Spring 9 Jet
Fig_ 12_ Starting fro_ _oId_ _ _uc_ion chg_ber _ o. Ad__ug_,_g _u_
1 Link 3_ Damping piston 1 1 Lock_ng spring
2. _e_u__ gpr__ng 4_ VaCuum piston 1 2. Lock nut
3 L 5 Throttl8 flap 1 3 Jet sleeve
. eVer 6 _h _ '
. anne 1q. Wggher
7_ Housing 15. Bridge
8 Fuel needle 16. _hanngl
_ when it passes through the constriction known as
the bridge (1 5, Fig. 1 3). _
Fuel is supp Iied to tfe flow of aì r th rough thg jet so that the carbureMors _bo accordance with
which opens out at the bridge. the continuously variab Ie principle.
The vertical position of the vacuum pigton ig deter- In order to prevent eKcessively r8pid movements
_ mined by the d ifference between the vacuum in Of the vacuum Piston, there is a damping piston
the carburettor and atmospheric presgure gince (3) WhiCh runs ín an oil-f_l led cylinder.
_ the top of the piston has access to the space
between the throMle flap 8nd bridge, whereas Idling
' the underside of the piston is influenced by atmos- When the engine is idling, only a gmal_ amount oF
, phefic pressure_ When Ioading on the eng ine fuel,/air miKture passes th rough the carburgttorg.
inCfeases, the degree of vacuum also increases, The throttle flgp _g heId gl_ght_y open by the id_ ing
_ SO that fhe piston and the tapered fuel needle risa screw (1 , Fig. 1 4). The idle adj ustment on each
gnd pefmit an increased amount of fuel/air miKture carburetfor is done independently. The ghgft bgt-
to Flow to the cyIind8rs ween the carburettors, see Fig. g, is not per-
The supply of fuel and air is thus dependent on manently fiKed to the throttle f_ap spjndle6 but ig
the degree of vacuum in the carburettor venturi, flexibly mounted in the ends of the)gverg. 2 - 7
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