Revision as of 07:06, 31 July 2011

See Carburetor Overview. The carburetor mixes air with gasoline in the proper ratio for all conditions. 14.7 to 1 by weight is the chemically correct ratio, but engines can work with 8:1 (very rich) to 22:1 (lean burn). For best power, it's about 12:1, but for best econonmy is is about 18:1. The stock Hitachi carburetor (when in good condition, i.e. not worn out) does an excellent job of providing superb economy but providing a rich power on demand. The Hitachi keeps in within the appropriate range for all throttle openings, temperature and loads. No dyno tuning is necessary. Since it works on airflow, not engine size, the Datsun 1200 Hitachi works acceptably on engines from A10 to A15 without changing the jets. As the airflow changes, the carburetor meters the fuel accordingly. Changing the jets is only necessarily for fine tuning of engine modifications (or if major modifications to the induction system are made such as a high-overlap camshaft).