FUNCTION
The idle circuit is contained in the first stage of the carburetor. Fuel is drawn up into a cavity within the carburetor cover through the idle fuel jet. Here it is mixed into an emulsion with the air entering through the idle air bore. By way of a channel, this emulsion flows to the fuel mixture outlet at the idle mixture screw and to the by-pass bores. The by-pass bores serve to improve transition from the idle jet to the main jet system when opening the throttle.
NOTE: The carburetor must be synchronized in order to prevent the possibility of performance problems
ADJUSTMENTS
- With car at full operating temperature, synchronize the throttle plates of each carburetor and adjust to specified idle RPM. (OE manual requires use of "Syncro-Test" device and adapter piece)
- Adjust idle mixture screws to the same position on both carburetors by blocking off the idle air bore in the top cover, one at a time, and matched the RPM drop. This procedure prevents damaging the idle mixture screws
- Observing a tachometer and exhaust analyzer, adjust the throttle valves and mixture as necessary to arrive at specified idle RPM and specified carbon monoxide.
