VI FlIEL CARBUllETl0N 4 37 sscounmv piston rides on a calibrated spring which attempts to Stig glmcn ggiln METERING keep the piston at the top of its cylinder This allows FUEL SECQNDAW Am the smallest diameter of the tapered metering rods to BOWL gER NG VM VE extend into the main metering jets and permits maximum fuel flow through the jets to the main well g W cavities W At idle part throttle or cruise conditions when manifold vacuum is high the piston will be drawn EQ Q down into the vacuum cylinder overcome calibrated O y spring tension and the larger diameter of the meter 7 EZ 4 ing rods will extend into the main metering jets y 7 restricting the fuel flow to the main well cavities An Z additional control is provided by the vacuum piston g limiter lever which 1s linked to the throttle lever by Z the accelerator pump rod This provides a direct Z relationship between meter1ng rod position and I d throttle plate opening Ji rum sscouoanv UNK l O MR RS l TLE CHECK E FUEL E nu Aww onscrmncss nra sa Smndary mn m 1 r rqc mun illwwr m When the throttle is closed the accelerator pump plunger is pulled upward by the pump link and com w onscmmcs presses the pump spring Fuel is drawn from the fuel PUMP Iii l2 bowl past the inlet check valve and into the pump numssn g s chamber The pump discharge needle is seated at this l KE time to prevent air from entering the pump chamber STROKE When the throttle is opened the pump plunger is nmsrcnscx mm n E moved downward by spring action causing the inlet Kim VALVE check valve to seat and forcing fuel into the discharge ATH lm sEDl passage The seating of the inlet check valve prevents PUMP fuel escaping back to the fuel bowl The pressure of UNK the fuel in the discharge passage lifts the discharge needle off its seat and sprays the fuel out the dis E K charge nozzles When the pump plunger has completed BALL DISCHARGE its travel downward the discharge needle seats to pre M I W67M M NQZZLE 4451 vent air entering the discharge passage assuring a solid fuel supply for the next pump stroke At high speeds a vacuum develops at the pump dis QQ k charge nozzles The pump air bleed check ball pro A GE vides a vent to the discharge nozzles and prevents l gfTED siphoning of fuel from the discharge passage The air Ij L GER gilegieis sealed by fuel pressure during the discharge g g GE Fm E l l l clmm inter cnzcx runorrnz r During heavy road load or high speed operation the VALVE SEATEM lgzvl ihj fuel air ratio must be richened to provide increased Air engine power Power enrichment is accomplished by means of two Q Fue Ausova calibrated metering rods yoked to a single manifold vacuum actuated piston fig 4 66 The metering rod Fly 4 G5 PII Clmllll