RCB 9D-8 Model "BC"


	ROCHESTER CARBURETORS Bulletin 9D-8 August, 1951
	Bulletin 9D-8 August, 1951 Model "BC" Page 11 ROCHESTER PRODUCTS, DIVISION OF GENERAL MOTORS, ROCHESTER. NEW YORK 3. Check all parts for wear. If wear is noted, defective part must be replaced. Note especially the following: (a) Check float needle and seat for wear. If the wear is noted the assembly must be replaced. (b) Check float button for wear and float for dents. Check floats for leaks by shaking. (c) Check throttle and choke shaft bores in throttle body and air horn castings for wear or out of round (d) Inspect idle adjusting needle for burrs or ridges. Such a condition requires replacement. (e) If wear is noted on steps of fast idle cam, it should be replaced as it may upset engine idle speed during the choking period. (f) Inspect pump plunger leather. Replace plunger if leather is damaged.

	4. Inspect gaskets to see if they appear hard or brittle or if the edges are torn or distorted. If any such condition is noted they must be replaced. 5. Check to see that lower end of suction tube is tight in seal in throttle body. If not, a new seal will have to be installed after the carburetor is assembled or poor choke operation will result from vacuum leak. 6. Inspect suction tube hex nut packing. If it appears unduly compressed or out of round, it should be replaced. 7. Check filter screens for dirt or lint. Clean and if they are distorted or remain plugged, replace.

	ASSEMBLY AND ADJUSTMENT 1. Install idle stop screw in throttle lever 2. Screw idle adjusting needle and spring into throttle body until it is finger tight. Back out screw 1-1/2 turns as a temporary idle adjustment. Make final adjustment on engine. 3. Install fast idle cam with letters HP facing outward 4. With bowl upended and suction tube projected over edge of flat surface, place new throttle body gasket into position and attach throttle body. Tighten screws evenly and securely. NOTE: New choke suction tube seal, if needed, will be installed after carburetor is completely assembled.