RCB 9D-9 Model "4GC"


ROCHESTER CARBURETORS Bulletin 9D-9 January 1952
Page 14

ROCHESTER PRODUCTS, DIVISION OF GENERAL MOTORS, ROCHESTER, NEW YORK

FLOAT BOWL DISASSEMBLY (Cont'd) size from the jets on the secondary side they must always be installed on the pump side. 3. Remove the power valve and fiber gasket from the pump side. 4. Remove three attaching screws and lock washers from Venturi cluster on inlet (secondary) side. Then carefully remove venturi cluster and gasket. 5. Remove both main metering jets from the inlet (secondary) side. NOTE: These jets are also stamped with the last two digits of the jet part number and must always be installed on the inlet (secondary) side of the carburetor. 6. Remove the pump return spring from the pump well with a pair of long-nosed pliers. 7. Carefully invert the carburetor bowl and remove the aluminum pump inlet ball and the brass pump outlet needle. (Figure 7-15.) NOTE: NEVER SUBSTITUTE A STEEL BALL FOR THE ALUMINUM BALL. 8. If necessary, remove the pump inlet filter screen and retainer from the bottom of the float bowl.			ALUMINUM BALL
			Figure 7-15

THROTTLE		BODY DISASSEMBLY

3. 4. 5. 6.	Place carburetor in inverted position. Remove throttle body from carburetor bowl by removing three 10-32 attaching screws and lock washers and one large 3/8-24 attaching screw and lock washer from the center of the throttle body. Carefully remove throttle body gasket. Remove idle adjusting needles and springs. Remove fast idle screw and spring from throttle lever. Remove idle stop screw and spring from throttle body casting. NOTE: THE THROTTLE BODY IS SERVICED AS A UNIT LESS THE THROTTLE LEVERS. TO REMOVE AND REPLACE THESE LEVERS PROCEED AS FOLLOWS: Remove two cotter pins from secondary throttle lever link.		8. Remove washer from upper end of secondary throttle lever link. 9. Remove secondary throttle lever retaining screw and washer. 10. Unhook inner end of override shaft spring (heavy spring). I I. Remove shaft override spring retaining screw from primary throttle shaft. 12. Remove secondary throttle actuating lever and override spring. I3. Remove secondary throttle lever link assembly. 14. Unhook secondary throttle lever return spring from secondary lever. 15. Remove secondary throttle lever from secondary throttle shaft. Then remove secondary throttle lever return spring from secondary throttle shaft.

CLEANING AND INSPECTION OF PARTS

Inspect idle adjusting needles for burrs or ridges. Thoroughly clean carburetor castings and metal parts in carburetor cleaning solvent. CAUTION: Choke Coil, Primary Venturi cluster (with pump discharge nozzles) and pump plunger should not be immersed in solvent. dean these parts in clean gasoline only. Blow all passages in castings dry with compressed air. Do not pass drills through jets or calibrated passages. Clean filter screens of dirt or lint. If they are distorted or plugged, replace. Check floats for dents or wear or burrs at hinge pin holes. Shake floats to check for leaks. Examine float needle and seat. If grooved, replace with a factory matched float needle, seat, and gasket assembly. Check choke shaft for wear in the air horn bores. If worn excessively, replace.			9. Inspect holes in inside and outside pump levers, fast idle cam, and throttle lever. If holes are worn excessively or out of round to the extent of improper operation of the carburetor, the worn parts should be replaced. 10. If excessive wear is noted on the steps of the fast idle cam, it should be replaced to assure proper engine operation during the warm-up and choking periods. 11. Inspect pump plunger leather, replace the plunger as an assembly it leather is creased or cracked. 12. Inspect the gaskets for flexibility. If the gaskets appear hard or brittle, they should be replaced to assure a proper seal. NOTE: Due to the close tolerance fit of the throttle valves, and the fact that the idle discharge holes are drilled in relation to a proper fitting valve, the throttle body and valve assembly should be replaced as a complete assembly when wear is noted at the throttle valves, or throttle body bores.