Pages 14–19 (6 pages)

Choke Systems, C.E.C. Valve and Idle Stop Solenoid

From the 1973 Rochester Quadrajet 4M, 4MC, 4MV Carburetor Service Manual (9D-5) with 1980–1986 Bulletins

Choke operation for the 4MV and for early and late 4MC carburetors: thermostatic coil, fast idle cam, vacuum break, unloader, secondary lockout, choke closing assist spring, bucking spring and delayed or dual vacuum break systems. Ends with the Combination Emission Control valve and the electric idle stop solenoid.

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What this section covers

  • 4MV choke
  • Early and late 4MC choke
  • Secondary lockout
  • Delayed and dual vacuum break
  • Choke unloader
  • C.E.C. valve
  • Idle stop solenoid
Year
1973, 1980, 1982, 1983, 1984, 1985, 1986
Make
Rochester
Vehicle
Carburetors, Components and Systems
Type
Service Bulletin, Service Manual, Specifications
Models
Quadrajet 4M, 4MC, 4MV; later M4MC, M4ME, E4MC, E4ME adjustment specifications
Publication
9D-5
Pages
79

What’s inside

1973 service manual

  1. Cover, Safety Notice and IndexTitle page for Carburetor Models 4M, 4MC, 4MV Service Manual 9D-5 (May 1973), and the Rochester Products Division safety notice and index. The note says to use this manual with sections 9D-5A, 9D-5S, 9D-5T and 9D-200 for complete service instructions.pp. 1–2
  2. General DescriptionIntroduces the Quadrajet as a four-barrel, two-stage downdraft carburetor. The 4M has a manual choke, the 4MC an automatic choke on the float bowl, and the 4MV a manifold-mounted thermostatic choke coil. Describes the small primary bores, large secondary bores, air valve, centered float bowl and aluminum throttle body.pp. 3–3
  3. Float System and Fuel Bowl VentsExplains the single-pontoon float, float needle pull clip, inlet filter and the two float needle designs: diaphragm-assisted and conventional needle and seat. Covers the idle vent valve, the thermostatic idle vent that opens above about 75 degrees, and the vacuum vent switch used with the evaporative loss canister.pp. 4–6
  4. Idle System, Canister Purge, EGR and Hot Idle Compensatorpp. 6–9
  5. Main Metering, Part-Throttle Features and Power SystemCovers the main metering system with plain tube nozzles, triple venturi, tapered primary metering rods and vacuum-operated power piston. Also the adjustable part throttle feature, the adjustable main well air bleed, fuel pull-over enrichment and the single and dual power piston springs.pp. 9–11
  6. Secondary System, Air Valve Dashpots and Accelerator PumpDescribes how the secondary throttle valves and spring-loaded air valve work with the eccentric cam and secondary metering rods in orifice plates, plus accelerating wells and baffle plates. Explains early piston-type and late diaphragm-type air valve dashpots, and the primary-side accelerator pump with its discharge check ball.pp. 12–14
  7. Choke Systems, C.E.C. Valve and Idle Stop Solenoidpp. 14–19
  8. Major Service Operations: Disassemblypp. 20–28
  9. Cleaning, Inspection, Assembly and Air Horn Installationpp. 29–32
  10. Revised Pages and 4MC Exploded ViewReplacement pages 31 and 32 dated November 1973: the rest of air horn to bowl assembly, vent valve and metering rod installation, and the exploded view of a typical Model 4MC Quadrajet with its parts list.pp. 33–34
  11. Adjustment Procedures and Specifications ReferenceDirects readers to the C and D sections of the Delco Carburetor 9X manual for replacement parts, troubleshooting, adjustment procedures and specifications for each carburetor model, and notes the tools and gauges available through United Delco suppliers.pp. 35–35

Bulletins 1980–1986

  1. 9D-5AM4MC and M4ME Adjustment Procedures (April 1982)Illustrated bulletin 9D-5A with carburetor identification and figures for float level, pump, air valve spring, choke coil lever, choke rod and fast idle cam, front and rear vacuum break, air valve rod, unloader and secondary lockout adjustments, using the angle gage.pp. 36–38
  2. 9D-5SM4MC and M4ME Specifications, 1982–1983pp. 39–49
  3. 9D-5SM4MC and M4ME Specifications, 1984May 1984 pages of bulletin 9D-5S for M4ME and M4MC carburetor numbers in the 17083291 to 17084296 range. The tables now use a choke stat lever with gage and add tolerances for float setting and angles.pp. 50–52
  4. 9D-5SM4MC, M4ME, M4MED and M4MEF Specifications, 1985pp. 53–57
  5. 9D-5SM4MC, M4ME, M4MED and M4MEF Specifications, 1986May 1986 pages of bulletin 9D-5S with 1986 adjustment specifications for M4ME, M4MC, M4MED and M4MEF carburetors, including carburetor numbers 17085283 to 17086598. Some table columns are lost in this scan.pp. 58–60
  6. 9D-5TQuadrajet 4MC and 4MV Troubleshooting (June 1980)pp. 61–65
  7. 9D-5-1AE4MC and E4ME Adjustment Procedures (April 1982)Bulletin 9D-5-1A for E4MC and E4ME carburetors: float gage checking, lean and rich mixture screw bench adjustments, idle mixture, air valve spring, choke coil lever, choke rod and fast idle cam, vacuum break, air valve rod and secondary lockout, with angle gage tools J-26701 or BT-7704.pp. 66–68
  8. 9D-5-1SE4MC and E4ME Specifications, 1982–1984pp. 69–76
  9. 9D-5-1SE4MC, E4ME and E4MED Specifications, 1985–1986May 1985 and 1986 pages of bulletin 9D-5-1S for E4ME, E4MC and E4MED carburetors. The 1986 page adds solenoid adjust screw and solenoid stop screw columns. Final page is page 79 of the book.pp. 77–79

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