Cars and Trucks
A
ACF-Brill Buses
Aero Coach
Ahrens Fox Fire Trucks
American Bantam
American LaFrance
American Motors
Auburn
Autocar
Available
Avanti
B
Biederman
Bricklin
Brockway
Buick
Buick 1961-1990 8 cylinder
Buick 1935-1960 8 cylinder
Buick 4 & 6 cylinder
Rochester Carburetor Parts. Carburetor Doctor carburetor rebuild kits, floats, choke pull offs, choke coils and other parts for Rochester carburetors are here. We have ethanol-compatible parts for all Rochester carburetors from the first Model AA carburetor in 1949 to the computer-controlled QJets of the 80's and on to aftermarket Edelbrock Quadrajets and marine carbs.
Apr 28, 2016 When discussing Quadrajet models, the number 4 means a four-barrel carburetor. The “M” after that, is a style/model type. Early Rochester four barrels were a “G” series. So, a 4M is a Quadrajet, and a 2M is a two-barrel Dualjet. The next letter, V, C, or E stands for the type of the choke’s thermostatic coil. Please keep in mind that these manuals may span several carburetor models and may not be your exact carburetor. Use these manuals as a general reference only. Don't forget to visit the technical pages for your specific carburetor. More manuals for specific carburetors may be available there. Aisan Rebuild Manual. Marine Electric Choke Quadrajet Carburetor with a Mercruiser Linkage: View Picture Gallery. This is an electic choke upgrade. We offer this unit for. 4.3L, 5.0L, 5.7L, and 7.4L engines. Fits Mercruiser Marine, Marine Power Marine, and Chris Craft Marine only. Remanufactured Rochester Marine Carburetors Starting at $269.95.
C
Cadillac
Checker
Chevrolet
Chevrolet 1928-1960
Chevrolet V8 1961-1990
Chevrolet 4 & 6 cylinder 1961-1990
Chevrolet/GMC Trucks V8
Chevrolet/GMC Trucks 4 & 6 cylinder
Chrysler
Chrysler 8 cylinder
Chrysler 6 cylinder
Clark Cortez
Corbitt Co.
Cord
Crosley
D
Dart Truck
DeSoto
Diamond T
Divco
Dodge
Dodge V8
Dodge 6 cylinder
Dodge Truck V8
Dodge Truck 6 cylinder
E
Edsel
Essex Terraplane
F
Fargo
Federal
Fitzjohn Coach
Flxible
Ford
Ford V8 4 barrel
Ford V8 2 barrel
Ford 4 & 6 cylinder
Ford Truck V8
Ford Truck 4 & 6 cylinder
F.W.D. Trucks
G
GMC Trucks
Graham-Paige
H
Hahn Motors
Hall-Scott Truck
Hudson
Hug
Hupmobile
I
Indiana
International (IHC)
J
Jeep
K
Kaiser-Frazer
Kenworth
L
Lafayette
Lancer
LaSalle
Lincoln
M
Maccar
Mack truck
Madson
Marmon-Herrington
Maxim
Mercury
Mercury V8
Mercury 4 & 6 cylinder
Moon
Motor Coach Industries
Motoresearch
N
Nash
O
Oldsmobile
Oldsmobile 8 cylinder
Oldsmobile 4 & 6 cylinder
Opel
Oshkosh Truck
P
Packard
Peter Pirsch & Sons
Pierce Arrow
Plymouth
Plymouth V8
Plymouth 4 & 6
Pontiac
Pontiac 8 cylinder
Pontiac 6 cylinder
Pontiac 4 cylinder
R
REO
S
Seagrave
Simplex
Southern Coach
Sterling
Stewart Truck
Studebaker
T
Terraplane
Transicold
Transitier Truck
Tucker
Twin Coach
V
W
Ward La France
White
Wiljack
Willys Overland
Winpower
Carburetor Technical Information
Rochester & Carter Quadrajets
Quadrajets were used as original equipment on many vehicles from 1965 to 1990. Over 100 million have been produced.
1966 Rochester Quadrajet used on 327 Chevrolet engine with manual transmission, no. 7026203 - number is on the blue 'bottle cap' visible on the throttle side
Design
The QJet is a large 4 barrel carburetor that has a small primary side for fuel economy and good emissions and a large secondary side for good performance. QJets have a maximum airflow of from 750-800 cfm. Because the secondary side of the Qjet opens according to the airflow requirements of the engine, the same basic carburetor size can be used on a large range of engine sizes. The basic 750 cfm QJet casting is used from 231 CID to over 400 CID - the big secondary air valves open only as the engine breathes. For example, on a mild 350 Chevy the air valve will never open all the way - because the motor can't use more than 600 cfm or so.
1980 Chevrolet truck Quadrajet, M4MC type (hot air choke), no. 17080213.
M4MC Quadrajets have an integral choke and a different airhorn design; also, the throttle shafts are longer than in 4MV carbs. Starting in 1968 carb numbers were stamped on the driver's side, near the back.
Rochester Quadrajet Diagram
Identification
Rochester Quadrajet Manual
There are three basic types of QJet: the original 4M (starting in 1965), M4M (1975 onward) and E4M (from 1979). All QJets had automatic chokes, of which there are two basic types - integral (choke coil on the carb) and remote (choke coil on the manifold). 4MV carbs have the choke coil on the manifold and 4MC carbs have it on the side of the carb in a housing. An M4MC carb has a choke coil on the carb; and M4ME carb has the same type fo choke coil, but with an electric heater element in the choke coil.
Choke parts, primary metering rods and throttle shafts are not interchangeable between 4M and M4M carbs.
Oldsmobile M4MC Quadrajet carburetor, showing the front fuel inlet used on BOP (Buick-Olds-Pontiac) carbs
Evolution
- 1965-66 4MV, 4MC: hydraulic piston damped air valve; originally came with diaphragm-type fuel inlet valve - now upgraded with needle/seat type; 4MV (remote choke) used on Chevy starting with 1965 396; Oldsmobile used the 4MC on Toronado in '66
- 1967-1971 4MV, 4MC: vacuum break used to damp air valve instead of piston; fuel inlet thread is 7/8'-20 on most carbs
- 1972-1979: 4MV carbs are used on cars until 1974; trucks until 1979; fuel inlet thread changed to 1'-20 in '72
- 1975: M4MC carbs have different metering rods from 4MV and have a carb-mounted choke; used on passenger cars and some trucks from 75-up
- 1980: E4ME computer controlled carb
- 1985: M4MED electric choke carb with dual capacity pump solenoid used on Federal trucks and various Canadian vehicles
- 1985: M4MEF with adjustable secondary air bleeds used on 454's with HD emissions, E4MED and E4MEF in California
- 17088152: the last automotive Quadrajet number (an E4ME)
- 17089112: the last Rochester Quadrajet number - a 4MV used on Mercruiser 502 MAG engines