1	THE CARBURETOR OR HOW I LEARNED TO LOVE THE ROCHESTER
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3	OVERVIEW Operating Principles Primary throttle system operation and calibration Secondary operation calibration and setting Other suggestions Not a how to do a rebuild
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5	CARBURETOR OPERATING PRINCIPLE
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7	AIR FUEL RATIO VS POWER
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11	STOCK MOTOR HOME CARBURETORS AND PARTS 73-77 455 engine Fed 7043254, pri. rod 50D, jet 70 75-76 455 engine CA 7045554 pri. rod 50D, jet 68 77-78 403 engine Fed 17058254 pri. rod 17056953, jet 76 77-78 403 engine CA 17058559 pri. rod 17051353, jet 78
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13	Primary Metering Rods, Jets and Power Piston 455 engines: increase jets to #71 or 72, stock rod-50D 403 engines: increase jets one or two sizes. More with headers. May have to change rods. Tune to best a/f ratio if possible 455, 403 rods are different Power piston spring 4-8 in. vac. Part 7036019 best.
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15	Primary and Secondary Throttles Secondary opened progressively by primaries significant size difference Check primary throttle shaft for wear and bush if necessary Check that accell. pedal fully opens throttle
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17	SECONDARY AIR VALVE
18	SECONDARY AND AIR VALVE OPERATION
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20	SECONDARY METERING RODS AND HANGER Stock 455and 403 Rods marked CJ Stock rod hanger marked “K”. “K” Initial height 0.565 in. Replacement “V” 0.615 in. is richer.
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22	AIR VALVE SETTING Check or remove choke air valve lockout lever. Check or replace plastic eccentric cam. Determine air valve moves freely. Adjust air valve spring- 3/4 turn past balance point. If spring is too tight, the secondaries will come in late or won’t come in at all. If set too light, the engine will tend to bog under full throttle
23	Air horn underside (Cover Plate) Note underside of secondary air valve Make sure secondary feed tubes are secure Check air horn for warpage. Find a better one from any M4 Quadrajet
24	FLOAT BOWL UNDERSIDE Fuel Well Plugs Fuel well plug leaks are a common cause of idle problems or poor mileage. Seal these with epoxy to avoid fuel dripping into throttle body.
25	OTHER SUGGESTIONS Check for vacuum leaks-heater system -vapor recovery-brake booster-cruise control-distributor advance-carburetor mounting gasket. Install an oxygen sensor and air/fuel ratio meter to tune and maintain carburetor in proper range. One wire unit for stock manifolds. Locate on left side just behind manifold. Three wire for headers located in collector area. Cinnabar has rebuilt, calibrated carburetors for sale. Edelbrock has a street legal, tunable replacement.
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