TUNING CARBURETTORS FOR COMPETITION EVENTS.

THE CLAUDEL-HOBSON.

WHEN endeavouring to obtain the maximum power and acceleration from any carburetter it is practically impossible to secure any setting which will also ensure economical consumption, though this is an ideal for which designers and manufacturers have striven for years. In the Claude-Hobson carburettor, incorporation of a patented approximated power jet, which, operating when full power is required and at no other time, enables the most economical mixture strength to be used for all running conditions, except when the engine is required to work at its full capacity. The object of the power jet is to provide the slight amount of extra fuel required of the sectional view herewith, and consists simply of a calibrated hole (K) in the plug (L). All petrol enters the diffuser by way of the main jet (K), through which it flows into the three concentric tubes (B, N & M). The outer tube (P) is an air tube only and contains no petrol. The tube (B) is a starting and slow running tube. The holes (j” J) near its base admit petrol which has entered the diffuser through the main jet (K). The delivery of petrol to the engine, when idling, by way of the slow running jet delivery hole (C) is regulated by the restriction (X), which is the actual slow running jet. An air supply is drawn through hole (DD) immediately above the restriction (X). The power jet is of the plain