The Stovebolt Site Forums The Shop Area Engine Shop Quadrajet Identity Crisis

The carburetor on my truck has been giving me problems for some time. Hard starting, low power, slow response... you get the idea. I decided to rebuild it, but I can't figure out what model I have. The stampings on the body are 17058213 2837 BJB. This cross references with nothing I have found.

Also, this apparently ran like crap partly because it has no choke control. I managed to figure out it uses a divorced choke, but i have no choke coil or linkage. The engine never had anything for it, the holes are not tapped. I need some kind of choke control, but I also keep getting the run around. The carb is a Carter reman that the PO just slapped on and hoped for the best, and faith didn't get him far apparently. Can anyone point me in the right direction? Or should I just toss this, and buy a new Edelbrock?

It would help if we knew what engine you are working with. Q-jets are Rochesters, is your carb remanufactured by Carter? More info please.

The engine is a standard 350, overbored .030" with the cam it came with. The paint and crank bearing ends point to a passenger car, but it was placed in a chevy 2 ton at some point in its life. I know Carter was tasked with picking up production when Rochester was insufficient. My understanding is that they are identical in parts, but the stampings changed, that is why I mentioned it.

Look at Xena's last post. The carb is for a 1978 Chevy with manual transmission.

Paint color means little as GM painted all engines corporate blue starting in 1977.

So I have a 4MV? Looking it up online creates incompatable gaskets, but I guess it is a start. Didn't realize they changed to one paint color, I thought they used red for truck engines.

You have lots of pictures. However, I can't see what the choke rod is connected to. Is it just dangling?

https://drive.google.com/drive/u/0/folders/0B6Aw4aYru4MTSk9ENS1OR2VfRWc

https://www.carburetor-parts.com/search.asp?keyword=17058213&search=search

Listed in the link above is the choke and rebuild kit that you need. If your manifold is not drilled for said choke, you have mismatched parts. It's likely you could drill and tap the manifold pretty easy, or as a last resort, put a manual cable to it.

Joe, I didn't find a Choke kit to install on my truck but I did notice they have electric conversions, so I'll go with that. The rest is a freaking life saver though. One would think the better known carbs on the market would have more definitive support, but alas.

Gord&Fran, The rod to the choke plate was indeed just dangling, the screw backed out and the plate was just hanging. Definitely wasn't helping the situation.


I read that the fuel wells have this nasty habit of leaking. If I find a leak, anyone here have a foolproof way of removing the old plugs to install new ones?

I do like Rochester. But the more I read about your particular carb, what you are preparing to do and buy and fix, the more I would toss it in the parts pile. If you have the money, YES, get a new Edelbrock. They are Carters. Both are cast by Weber.

AFB stands for "Aluminum Four Barrel" Carter started producing this carburetor in 1957 and were in use on new cars until 1971
AVS stands for Air Valve Secondary. Used from 1966 thru 1971. Features spring loaded air valve above secondary bores.
Edelbrock produces new AFB's & AVS carburetor with minor changes. Edelbrocks version of the AFB is called their Performer Series. Their AVS version is called Thunder Series.
Later aftermarket versions of the AFB was the 9000-Series and the Competition-Series. The 9000-Series were designed for street use and were available with flow capacities of 400, 500 and 625 cfm and featured electric chokes. The Competition-Series were offered in 500, 625, and 750 cfm capacities with a manual choke or no choke.

"Definitive support"? There is more info on QJet family than anything else on the internet. Except the Kardashian family. Both families have a love/hate following.

A few misconceptions in this thread:

(1) Rochester started producing the Q-Jet in 1965.
(2) Carter produced millions of Q-Jets under license from GM FOR O.E. GM applications. The lettering on the drivers side of the bowl differed, but the same identification number was used. Carter and Rochester with the same identification number use the same parts.
(3) Q-Jet numbering is normally 7 or 8 digits beginning with 70 (7 digit) or 170 (8 digit). EXCEPTIONS:
(3-A) Most O.E. Q-Jet ID numbers, whether Rochester or Carter from the late 1960's were FIVE digits (the leading 70 was omitted). Just append 70 to the front and use it as a 7 digit number
(3-B) Carter also made aftermarket Q-Jets. These have the Carter style number (4 digits, followed by the letter S as in (S)am).
(4) The clones are NOT Carters. They are a redesign of the AFB done when Carter was owned by Federal Mogul (Carters were too expensive, FM wanted to sell them cheaper than Holleys, AND THEY COULD with the new ones!) We sent our initial order back to FM, as did many Carter distributors.
(5) Bart is mostly correct on the range on the CARTER AFB, however, they were still used as O.E. on marine and high performance export (no smog) as late as 1980.
(6) The Competition Series Carters were made in 500, 625, and 750 versions, but there was no 625 chokeless, manual choke only on the 625
(7) There are two excellent books on the Q-Jet, plus a third one with good information.
(7-A) Rochester Carburetors by Doug Roe and Bill Fisher (Doug was the design engineer on the Q-Jet)
(7-B) Q-Jets (maybe not exact title) by Cliff Ruggles (Mr. Q-Jet) - among the top 5 carburetor books I have read in the last 55 years!
(7-C) There is excellent Q-Jet information in the book by Jim Hand on Pontiac engines (see Joe H.'s post above)
(8) The Rochester well-plugs on the 1965-1967 models did leak. The issue was resolved with the 1968 models.

And finally: Bart mentioned the Carter AVS which is the worst 4-barrel Carter ever built (Opinion). Chevrolet tried it one year, and discontinued it. Chrysler couldn't pass smog emission without it in the 68-71 years. As soon as the TQ was available, Chrysler discontinued the AVS. Today, they are exceptionally valuable (to collectors only) because virtually every one was junked 7 nano-seconds after the factory warranty expired.
Carter offered it, at least in the catalogs, as aftermarket in 1972 (we were a Carter distributor at the time), but I have NEVER seen one, or spoken with anyone who has seen one!

Jon

The main problem with a different carb is that all the peripherals must now change to accommodate it; throttle linkage, pcv setup, fuel pipe, air filter, etc. Adding the extra $200 of a new vs rebuilding carb to that, and I might seriously consider the headache of TBI. The definitive support takes shape in "look for this, this, and this, and if it has it you have this model of carb. The quadrajet is the first object I have ever encountered where the serial number directly and definitively corrolates with what parts fit. All other instances gives more of a "be advised" notification.

If you are referring to my info, please notice it says CARTER............1957
I did switch paddles in the middle of the stream, went from QJet to AFB without notice.

Got the center paragraph from the internet.

And:
https://www.hemmings.com/blog/article/carter-4-barrel-carburetors-2/

https://www.carburetor-parts.com/Carter-AFB-Carburetor_ep_277.html

Bart - the only two of the above to refer to your data was the first paragraph, the clones are NOT the same as the original Carters; and the clarification about the 625 CS series chokeless only.

Jon.

Well, I went out to the shop yesterday and dug out my stash of 3 Q-Jets. One Rochester and two were Carter manufactured. I stand corrected. I’ve been around since long before the introduction of the Quads. Guess I never paid any attention to who was making them.

Quadrajets had some labor pains in the birthing process and the first year of production was an unmitigated disaster. I attended one of the first technician training seminars GM offered on the carb at the their training center in Memphis, in 1966, I believe. An innovative (and unsuccessful) approach to controlling the float level was used on the first ones which included a needle valve with a rubber diaphragm incorporated that was supposed to use fuel pump pressure to assist the float in closing the valve. Those diaphragms ruptured frequently, and resulted in massive flooding. There was absolutely nothing GM could do to solve the problem, so all those carbs were recalled and replaced with ones with a conventional needle and seat. A few aftermarket fixes were tried, none of which were successful. The leaky plugs at the bottom of the float bowl could be fixed by gently peening the metal around the edge of the plug, but the best fix was to use a fuel-resistant 2-part epoxy coating that some of the carb kit vendors offered and slathering on a generous layer during a carb rebuild. Some rebuild kits also had a thick soft plastic filler block that molded itself to the shape of the well plugs and did a fairly good job of sealing seep leaks.
Most Q-jets had 23 consecutive adjustments to make during the reassembly process, with several of them affecting the accuracy of the following setting. Make a mistake early on, and errors would stack up, making performance a nightmare, particularly where automatic choke and fast idle performance was concerned. The adjustment of the tension on the air valve spring was also a very critical setting which affected the transition from primary to secondary throttle operation. A lot of the bad publicity the Q-Jet got was the result of hurried rebuilds by guys trying to beat the flat rate labor time, not the fault of the carburetor's design or operation.
Jerry

Lets see a picture of the manifold on the choke side.

Jerry is correct about the early issues:

In 1966, the internal dashpot was discontinued. The 1965 units may be bored, and custom sleeves made and inserted.
In 1967, the "umbrella" fuel valve was discontinued. The earlier units may be converted by plugging the transition channel, milling and tapping the body for the conventional fuel valve, and installing the new fuel valve. The aftermarket "press-in" valves would work, but only if all of the planets were correctly aligned As soon as the planets lost alignment.........
In 1968, the well plugs were redesigned, and spun rather than pressed.
There were two different changes to the fuel inlet fitting, from 3 to 5 threads, and from 5 to 8 threads.
In 1969, the plastic fast idle cam was discontinued, and steel service replacements issued for earlier units. The plastic units (90 different) are in demand by the numbers-matching folks.
Virtually all Q-jets by now will require throttle bushings to be installed on the primary side. MEASURE FIRST! If the clearance does not exceed 0.009 inch, don't re-bush!

By 1968, the Q-Jet was an excellent street carburetor.
By 1969, the Q-Jet was a great street carburetor.

The 1965~1967 units are best left for the numbers-matching folks, although ALL of them can be made to perform WELL. It is a matter of money, and the experience of the rebuilder.

Over a few years, from about 1971~1974, the float pin placement was changed. This change allowed better fuel fill for highly modified race engines (450 HP or more). This change makes the Q-Jet an excellent race carburetor for straight-line racing. Racing with corners is possible, IF REQUIRED BY THE SANCTIONING AUTHORITY. Other carbs are easier to make go fast around corners.

The upper limit (it is continually pushed) for horse power for the Q-Jet is currently about 550.

Anyone seriously considering the use of a quadrajet, especially for racing, should consider the three books in my previous post in this thread. All are in paperback, all are inexpensive, and all WILL help with Q-Jet understanding.

Finally, there are a LOT of CHEAP SHORTCUTS to fix issues with the Q-Jet. These were designed to separate the owner from his/her income, but not to work properly!

Jon.

Then, in the mid-1980's they put that cotton-picklin' mixture control solenoid in them, and really messed up what had been one of the best carburetor designs of the 20th. Century! Those things had their own set of gremlins to deal with, which never got fully resolved before throttle body injection came along!
Jerry