Green’s Dictionary of Slang

(Aus.) a carburettor.

1957		‘Nino Culotta’ They’re a Weird Mob (1958) 47: ‘Carburettor, matey,’ said Joe. ‘We’ll start on the carby.’.
1965		W. Dick Bunch of Ratbags 219: All our fleet had straight-out exhausts, a few had twin carbys.
1977		A. Mackay Life Pieces II 89: Randy had a double-overhead-camshaft Maserati with four webers. We were always pulling down the carbies to get more out of them [AND].
1986		T. Winton That Eye, The Sky 76: Fanbelts. Carbies. Tools.