What was found
SINCE INSTALLING ONE-PIECE VENTURI, ENG. HAS PROGRESSIVELY RUN RICH - HAVE HAD CARB. APART ON 2 OCCASIONS TO CHECK FLOAT LEVEL, VENTURI, ACCELL. PUMP, AND NEEDLE AND SEAT FOR PERFORMANCE, MIXTURE HAS TO BE LEANED (1) KNOB. VIOLENT SHUDDER ON POWER REDUCTION UNLESS MIXTURE IS LEANED FIRST. SUSPECT CARB. NEEDS DIFFERENT DISCHARGE NOZZLE WITH THIS VENTURI.