strombergCDSB 1

SERIES STROMBERG

C D

Constant Yacuum

7ENIThh CARBURETTERS SERYICE BULLETIN

PRINCIPAL FEATURES

This Stromberg " CD " or constińt depression instrument is difterenl from previoos carburcuers we Kave manufactured c< ftxed choke tubc design. It operates on the ” constant vacuum " principle. the cKokc arca and the jet orifice varying accordlng to the degree of throttle openlng and the speed of tho englne which will aiter according to the load.

11 is a simpJe, compaa ano dustproof instrument with concentric floatchamber surrounding the fet orifice with its attendant advantages ovcr the morc crthodox out-rigged floatchamber some distance away from the jet.

Three principal dte-cast aluminium casting* are used in the ccnstruction. the main body. suction chamber cover and the floatchamber. The air va!vc body and hstismg for the jet asscmbly are also castingi rcsulting in an oxtcemely light-weight carburcttor re^!ative to borę sito and air f!ow.

The " CD " carburcttor is suitable for installation between horiaontal and scml-downdraught, the features which oermit this indinaticn are tlve concentric floatchamber and a centra! jet orifice which gives a very stcep flooding mgle, ensuring good operation and stable idling in hilly termin with no tendency to cut out on fast cornerir.g.

The carburcttor his a cdd start device intcrccnnected with the throttle to provide for a ipecific degrcc of throttle opening to eniurc a sultable fast-idle as necessary when tho motor is cold.

PRINCIPLE OF OPERATION

The pctrol inlct I, a parallcl tubę to accommodate a flexib!e fuei pipę is at the sido of the main body. From here fuel passes into tbe floatchambor via the ncodle seating 5 whoro the flow is controllcd by the needle 8 and tho twln expar>d«d rubber fioats on a cccnmon arm 7. As the pctrol lcvcl rises the float lifts and, by rnearw of the fioat arm and tag. doses the needle cn its seating when tbe correct level hm boen attalned. With the cr.gine running, petrol is drawn from the floatchamber. the float desccnds and mon* fuei is then admitted through the needle seatiog. In this manner, the correct lovc! is automatically maintained the whole of the timc tbc ca/burettcr is in action.

The fuol fromihe floatchamber will rise in tbe jet orifice 19 via bdes 21 and 22 in the jet asscmbly. the fuel in the jet orifice bclng maintained at thesamc tcvcl as that in tbe floatchamber.

Sheet Ref. s SB,211

G.6609