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Mercruiser Carburetor parts

Rochester Quadrajet

Quadrajets were used as original gear on many automobiles from 1965 to 1990. Over 100 million have now been created.

1966 Rochester Quadrajet used on 327 Chevrolet motor with manual transmission, no. 7026203 - quantity is on blue 'bottle limit' noticeable regarding throttle part

Design The QJet is a large 4 barrel carburetor that a tiny main side for gas economic climate and good emissions and a sizable secondary part once and for all performance. QJets have a maximum airflow of from 750-800 cfm. Due to the fact secondary side of the Qjet opens in accordance with the airflow needs of engine, the exact same fundamental carburetor dimensions may be used on a large number of motor sizes. The fundamental 750 cfm QJet casting can be used from 231 CID to over 400 CID - the top additional environment valves open just as engine breathes. As an example, on a mild 350 Chevy the atmosphere device wouldn't open up all the way - due to the fact engine can't make use of a lot more than 600 cfm approximately.

1980 Chevrolet truck Quadrajet, M4MC kind (hot-air choke), no. 17080213. M4MC Quadrajets have an integrated choke and another airhorn design; also, the throttle shafts are more than in 4MV carbohydrates. Starting in 1968 carbohydrate numbers were stamped regarding driver's side, near the straight back.

Identification you will find three basic forms of QJet: the original 4M (beginning in 1965), M4M (1975 forward) and E4M (from 1979). All QJets had automated chokes, which there are two main standard types - integral (choke coil from the carb) and remote (choke coil from the manifold). 4MV carbs possess choke coil regarding the manifold and 4MC carbohydrates have it on the side associated with carb in a housing. An M4MC carbohydrate features a choke coil from the carbohydrate; and M4ME carbohydrate has the same type fo choke coil, however with an electric powered heater take into account the choke coil.

Choke components, major metering rods and throttle shafts are not compatible between 4M and M4M carbohydrates.

Oldsmobile M4MC Quadrajet carburetor, showing the front fuel inlet utilized on BOP (Buick-Olds-Pontiac) carbs


  • 1965-66 4MV, 4MC: hydraulic piston damped environment valve; initially included diaphragm-type gasoline inlet valve - today enhanced with needle/seat type; 4MV (remote choke) used on Chevy beginning with 1965 396; Oldsmobile used the 4MC on Toronado in '66
  • 1967-1971 4MV, 4MC: vacuum break familiar with damp environment valve rather than piston; fuel inlet thread is 7/8"-20 on most carbs
  • 1972-1979: 4MV carbohydrates are utilized on automobiles until 1974; vehicles until 1979; gasoline inlet thread altered to 1"-20 in '72
  • 1975: M4MC carbohydrates have actually various metering rods from 4MV and now have a carb-mounted choke; applied to traveler cars plus some vehicles from 75-up
  • 1975: M4ME electric choke carbohydrate used on Cadillac
  • 1980: E4ME computer system influenced carb
  • 1985: M4MED electric choke carbohydrate with double capacity push solenoid applied to Federal vehicles and differing Canadian vehicles
  • 1985: M4MEF with flexible secondary air bleeds utilized on 454's with HD emissions, E4MED and E4MEF in Ca
  • the very last Rochester Quadrajet number - a 4MV utilized on Mercruiser 502 MAG engines

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