Probably18 years ago, I rebuilt my '70 GS 350. It's been running great ever since, but has always been a devil to start due to choke issues. Maybe I should've "choked" the idiot ex-brother-in-law who "rebuilt" the carb. I didn't realize for some time that he had no idea what he was doing. In the past few months I've been doing some research and have decided that I'll take on this carb, and make it right. The ID# is 7040244, which is the carb that came with the car. My biggest problem is that my super-mechanic put the thing on the motor without a choke or any linkages except for the throttle to make it go.....Can someone give me some ideas where to look for good info on these things? I've already been to a few places selling parts and such, but since I don't have all the info about what is supposed to be there, I'm not sure what I should buy. Any help I could get on this would be GREATLY appreciated.....
Best bet would to be buy this book. It's a good one. http://www.cliffshighperformance.com/buy_book_2.html
a couple pics here http://www.carburetion.com/CarbNumber.asp?Number=7040244 some parts here www.quadrajetparts.com I would also suggest searching EBAY for listings of your carb with pics. items you see over and over in listings are the ones original to the carb.
I would start over and contact Ken (Everyday Performance) for a replacement carb that is ready to run. Who knows what has been done to your current carb, it may never run right.
X2, you can spend a lot of money learning how to do it yourself or you can send it to Ken and know its done correct the first time. Sure beats taking it apart multiple times to get it right or trusting it with someone who claims to be able to repair the carb.
Okay....so I'm crazy....I want to do this myself. I bought Cliff Ruggles' book, I searched Ebay and about a dozen other websites for pics. I still haven't found the right info on what components should be present for a good working Q-Jet on my GS 350. There is a primary pulloff and a secondary pulloff on there. The original intake had a recess for a bi-metal spring. The Poston S-Divider on there now has provisions for a surface mounted bi-metal spring thermostat. I need to wrap my mind around just how the primary, secondary and spring work together. I'm unsure about where the linkage rod from the bi-metal attaches to the carb....Any suggestions? Any good guesses would be helpful at this point....Thanks!
Being that each Quadrajet was calibrated for the engine that it was meant for, the most important thing is to get the calibration right for the engine you intend to put that carburetor on. The primary pull off does double duty. It opens the choke a set amount, against thermostatic spring tension, when the engine fires on a cold start. This lets the engine run smoothly without loading up. The primary pull off also is linked to the secondary air valves to hold them closed until the engine's demand for air is there. It then allows them to tip in, instead of flop in, which would cause engine bog. The secondary pull off was added in later years. It opens the choke a bit more for better choke control, an emissions consideration. I wouldn't even bother with the secondary pull off.
Perfect......That's what I was looking for. So the secondary PO is the metal one on the "rearward" side of the carb, and the primary is the smaller plastic one on front, correct?
That is correct. BTW, if you have a Buick Chassis manual, it has an entire section on the Quadrajet. It explains all systems of the carburetor in detail, including primary and secondary pull off function.
did '70 7040240 carbs not have the secondary choke pull off ? only primary ? or was there a change over date ?thx DL
Yes, all 70 carbs had a secondary choke pull off. It provided increased choke control during warm up. While the primary choke pull off does double duty as a damper for the secondary air valves, the secondary choke pull off is for choke control only.
Hello Bob I am going down this road at this moment with my 1968 Wildcat., as when I brought it the engine smelt of gasoline and it was also leaking around the engine and into the oil pan. The information which the guys on here have given you is great and shows a lot of experience, skills and knowledge. If you are like me and I am only looking to make the car run as it should and get it to give you the best economy. You may wish to rebuild it yourself. One of my autoshop students at my school gave me a book by Cliff Ruggles called "Rochester Quadrajet Carburetors" isbn code 978-1-932494-18-1. Its a great book and has all the information which you need to rebuild your carb yourself. There are plenty of gasket sets around at most parts stores, however most of them are not compatible over a long period with ethanol gasoline. I found online, Daytona Parts in Florida, who just specialise in carburetors and they have been fantastic and they sell the gasket sets, which are compatible for those who use ethanol based fuel. They also offer the full overhaul service and will also rebuild parts from your carburetor. When I took mine off the car, all the bolts were finger tight and the gaskets fell apart in my hand, (I was amazed how well it was running in this condition and this is a testament to the durability of this carburetor). The throttle spindles were badly worn and I was able to send the base to Daytona Parts and have them re-bushed and reamed out. This I can do myself, however for what it cost for them to do it, I could not buy the correct bushes and reamers for that price. Therefore for less than $80, I was able to buy the parts and get the base overhauled. Cliff Ruggles book is interesting to read and leads you through the whole process and the all important stage of setting it up to run. Take care John
Thanks Larry , apparently someone changed my bracket out to a single pull off in the past 43 years . Ill have to find a parts carb . DL
