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P _ 16 _ 1 5 14 7 3 1 l ' _ 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 a 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 n 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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