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Old 03-30-2010, 12:18 PM   #1
rddaves54
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Question 4bbl quadrajet question?????

I have a 72 Chevy long bed with a 350 that has a 4bbl quadrajet and was wondering how best to fix it. I can buy on for $300.00 that has been rebuilt and guarantee. I thought about rebuilding myself but I read here somewhere that it is very hard to do and even if the kit works that does not mean everything will be correct.

The problem I am having is the engine does not want to stay running after I start it. I can get it to start but have to pump the gas pedal until it runs a minute and then it will stay running. I have run a few tanks of good gas through it with gumout gas cleaner added thinking this might help. The truck was in really bad shape when I got it.
I do not know too much about carburetors and want all the help I can get before spending that kind of money. I would like to keep a quadrajet.
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Old 03-30-2010, 12:22 PM   #2
One Chevy Scotty
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Re: 4bbl quadrajet question?????

I think that you can get one rebuilt and guaranteed for a lot less. I paid $165 to have one rebuilt (from their core) and that included one free tuning (adjustment) after I installed it. $300 seems high, you could buy a new edlebrock for that....it sounds like your problem is with the divorced choke. The choke is one the passenger side of the carb, it is a sring like device mounted in the intake manifold (if you still have a stock manifold) and connected to the carb via a steel linkage rod. It moves the choke butterfly to a closed position when the motor is cold. I would check that first, if the trucks runs fine after it is warm...

just my 2 cents.

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Old 03-30-2010, 12:24 PM   #3
don t. - 72gmc
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Re: 4bbl quadrajet question?????

I am not a mechanic in any sense of the word, but if you can read and follow instructions, rebuilding a Q-jet (2 or 4 bbl) is no big deal. I no longer have the links, but there is some real good info on this board, and the web with detailed instructions.

One thing that I do not think comes w/the rebuild kit is your accelorator pump, which is inside the carb. Mine had problems similar to yours, but after I did the rebuild. The local GM dealer had the part the next day.

HTH...good luck...don t. ....
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Old 03-30-2010, 12:46 PM   #4
rddaves54
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Re: 4bbl quadrajet question?????

Has anyone put on electric choke and how are they? Do they work and are they pretty easy to install? Parts store here has one for $60.
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Old 03-30-2010, 01:03 PM   #5
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Re: 4bbl quadrajet question?????

Interesting. I have the same issue with my '71. When it the engine is cold I need to feather the gas a little bit to keep it going. Once it's warmed up a touch it runs fine. I'm just learning about everything, but I assumed that's just the way it is with these engines when cold.
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Old 03-30-2010, 02:55 PM   #6
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Re: 4bbl quadrajet question?????

Quote:
Originally Posted by rddaves54 View Post
Has anyone put on electric choke and how are they? Do they work and are they pretty easy to install? Parts store here has one for $60.
I like the electric choke and they're not hard to install and set up.
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Old 03-30-2010, 04:27 PM   #7
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Re: 4bbl quadrajet question?????

Quadrajets aren't that hard to rebuild. It sound like the power pump is bad which means you have to dissassemble to fix it. A new Edelbrock is about $ 240 in these parts and a rebuild kit ia about $20 for the Quadrajet. Good Luck
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Old 03-30-2010, 10:35 PM   #8
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Re: 4bbl quadrajet question?????

Muscle Car on Spike TV did an episode of a Q jet rebuild a while back. Heres a link to the episode: http://www.spike.com/full-episode/qu...-rebuild/33035
Hope this helps!
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Old 03-30-2010, 11:02 PM   #9
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Re: 4bbl quadrajet question?????

Quote:
Originally Posted by rddaves54 View Post
Has anyone put on electric choke and how are they? Do they work and are they pretty easy to install? Parts store here has one for $60.
I put one on mine and it works pretty good. It has a thermostat that mounts to one of the intake manifold bolts. If your problem is just the choke then rebuilding won't help it. I'd fix the choke first and then see how it runs.

Last edited by highperf4x4; 03-30-2010 at 11:03 PM.
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Old 03-31-2010, 03:11 AM   #10
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Re: 4bbl quadrajet question?????

For $300 dollars, I would go with Sean Murphy Induction (SMI). I have only heard great things about him and if you call them, you can actually talk to him (I have before). When I get the money, thats what I will be running.
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Old 03-31-2010, 10:16 AM   #11
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Re: 4bbl quadrajet question?????



SMI did mine, and my truck has never ran better. Spoke with Sean many times on the phone during and after the process.

I did a bunch of research AFTER the fact, so i went back and checked all the air/fuel/idle bleed holes, etc etc, and his were right on the money with everything that I learned.

They are not hard to rebuild at all. But it was money well spent to have someone else do it!

J
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Old 03-31-2010, 11:21 AM   #12
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Re: 4bbl quadrajet question?????

r u aware that there is a fuel filter inside the carb? where the fuel supply line goes into it the large fitting comes off and theres a sintered bronze filter// i'd spend that dollar first b4 plunking down $300 but i'm not much on parts changing i like doing simple little cheapo things to get tings going
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Old 03-31-2010, 01:10 PM   #13
truckdude239
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Re: 4bbl quadrajet question?????

i paid224 buxs for my q jet online witha lifetime warranty and i haven't been very happy i got one from advance auto first and it was a bad one also i got another i just had built and will see how it goes but after thisone i am done with qjets
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Old 03-31-2010, 02:42 PM   #14
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Re: 4bbl quadrajet question?????

The thing about buying a Quadrajet from an autoparts store is that they are not specifically tuned to your application. Ive gone that route before.
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HEI, Curve kit, TH 350, 3.07 gears
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Old 03-31-2010, 05:21 PM   #15
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Re: 4bbl quadrajet question?????

Well, I just bought a 20buck kit from NAPA and rebuilt mine,,,, it is still on the workbench waitin to be put on,,,, but, it wasn't that hard,,, just don't take apart one day after being up for 20 hrs, then take a nap, go to work, get off work and try to put together,,,, NOT fun!
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Old 04-01-2010, 04:01 PM   #16
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Re: 4bbl quadrajet question?????

I have been tuning in a qjet for my 72 and can take it appart and put it back together in less than 20 minutes. I have been changing jets and rods to try to dial one in that wasn't set up for my application. I have spent a lot of time talking to Cliff Ruggles who wrote the book on qjet rebuilding. Your best bet is to get his book and rebuild what you have since it was made for your truck. I tried a Jet Performance qjet that had huge air bleeds and always ran to lean. I final got one with small air bleeds and now the truck runs better than it ever has. It had an Edelbrock on it when I bought it and wanted more throttle response and better gas mileage. All the work is paying off with great off the line power and the fantactic sound of the secondaries kicking in. It runs like it has EFI.

As everyone has mentioned check the choke first. If it a divorced choke it takes a special setup for the conversion to electric but I have seen them on line. Next you will need to clean all the passages and get a new accellorater pump. Be sure to get one that works with alcohol (dark blue I think). The rubber ones will deteriorate in alcohol.

The divorce choke carbs are a little harder to rebuild due to the linkage and how it is attached. There is a trick to lining it up when putting it back together.

Cliff has a tip in procedure for telling you if you are running lean or rich which works pretty well. I am using an Innovate LC-1 to dail mine in and it has worked great. One more jet change and I should have it.

STay with the qjet and get it working right and you will be very happy.
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Old 04-01-2010, 05:28 PM   #17
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Re: 4bbl quadrajet question?????

As mentioned above, get the cliff ruggles book. I plan on heading to the book store to get it today. With my new motor, longtubes, and free-flowing exhaust my stock rebuilt egr-cali emissions quad can't quite keep up with fuel demands It's way lean. To the poster way up on the page, being lean as well as the choke not functioning properly will both cause it to be tempermental when cold, mine is doggy and pops when cold
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