How to rebuild a Rochester Quadrajet 4MV carburetor

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For decoding the carb number, please see the following article for further information and assistance: '''[[Rochester Quadrajet carburetors: Identification and decoding]]'''
 
For decoding the carb number, please see the following article for further information and assistance: '''[[Rochester Quadrajet carburetors: Identification and decoding]]'''
 
[[File:Carburetor_Identification_Number.jpg|thumb|center|750x250px|Location of 1968-up Q-jet carb number. Before this the carb number was stamped into a round disc located on the driver side of the carb, towards the front]]
 
[[File:Carburetor_Identification_Number.jpg|thumb|center|750x250px|Location of 1968-up Q-jet carb number. Before this the carb number was stamped into a round disc located on the driver side of the carb, towards the front]]
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==Other considerations==
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*When getting a carb from another vehicle, whenever possible, get the factory cable bracket. Even if you're using an aftermarket intake, it might come in handy for making up your own bracket. And regardless if using an aftermarket intake or not, the bracket can be used to measure the correct cable/carb relationship for setting up whatever bracket that's used.
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*Make note of the engine displacement/engine VIN code. These carbs were used on 4.3L V6 through 7.4L V8 engines, so knowing what it came from gives a leg up on what may potentially need changed.
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*If the Q-jet is to be used with an automatic transmission that uses a detent (kick down) or TV (throttle valve) cable, be sure the throttle arm is correct (below, right). Many manual transmission-equipped vehicles are missing the lower part of the throttle arm (below, left); this is where the detent/TV cable ordinarily attaches.
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{|
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|[[File:TYPICAL MANUAL TRANS Q-JET THROTTLE ARM1.jpg|250px|Manual or TH400 trans throttle arm that's missing the portion below the throttle shaft center line where the detent/TV cable would be attached]]
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|[[File:LINKAGE TH350 CARB WITH AT.jpg|215px|Automatic trans throttle arm]]
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|}<br>
  
 
===B. Parts===
 
===B. Parts===
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[[File:Q-JET FILTER HOUSING GASKETS.jpg|thumb|300px|left|The two most used carb filter housing gaskets. Earliest was 7/8" (and are rare), later were all 1", early had gasket over the threads, late style had white gasket on end of housing before threads]]
 
[[File:Q-JET FILTER HOUSING GASKETS.jpg|thumb|300px|left|The two most used carb filter housing gaskets. Earliest was 7/8" (and are rare), later were all 1", early had gasket over the threads, late style had white gasket on end of housing before threads]]
 
[[File:REBUILT CARB TELL-TAIL PIN TO BLOCK INCORRECT AIR CLEANER STUD INSTALLATION.jpg|thumb|300px|left|Dead give-away of a rebuilt carb: Arrow points to tell-tail pin installed by rebuilders to keep the air cleaner stud from being inserted into the wrong hole]]
 
[[File:REBUILT CARB TELL-TAIL PIN TO BLOCK INCORRECT AIR CLEANER STUD INSTALLATION.jpg|thumb|300px|left|Dead give-away of a rebuilt carb: Arrow points to tell-tail pin installed by rebuilders to keep the air cleaner stud from being inserted into the wrong hole]]
[[File:TYPICAL MANUAL TRANS Q-JET THROTTLE ARM.jpg|thumb|300px|left|Manual or TH400 trans throttle arm that's missing the portion below the throttle shaft center line where the detent/TV cable would be attached]]
 
 
[[File:Secondary rods 002.jpg|thumb|300px|left|Selection of secondary metering rods: Lean left, rich middle, medium right]]
 
[[File:Secondary rods 002.jpg|thumb|300px|left|Selection of secondary metering rods: Lean left, rich middle, medium right]]
 
[[File:CHOKE BIMETAL COILS 2.jpg|thumb|300px|left|Several types of hot air choke thermostats]]
 
[[File:CHOKE BIMETAL COILS 2.jpg|thumb|300px|left|Several types of hot air choke thermostats]]

Revision as of 17:09, 18 January 2013

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