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Question about my 71, 350 auto. When I start the vette the smell in the garage is really bad..even on your clothes. The carb is a quadrajet with an Edelbrock tag. Runs great, idles great, starts up on the choke..no problem. It seems to idle to rich. Anyway to get rid of the smell? Will the idle mixture screws cure it? I hate to mess with it because it really runs well. Thanks, Bill
Try adjusting the idle mix. Also make sure your plugs, cap and rotor are good. And points if you have them. It's hard to tell in the pic, but is the choke opening up all the way when it's warmed up?
The first order of business is to check out the carb choke system and adjust it to work properly. That includes setting the 'fast idle' adjustment PROPERLY.
If set up properly, the choke plate will be almost closed off when you TAP (not stab to the floor) the accel pedal before starting a cold engine. And, once running, the idle speed should be in the 700-800 rpm range (without having to pump the accelerator before starting or constantly exercise it to keep it running). If it is running much higher than that, someone has increased the fast idle to compensate for a misadjusted choke. That would explain the excessive fuel fumes you are experiencing.
Curb idle adjustment screws should only be set when the engine is WARM. They should not be changed to deal with cold-start issues.
The first order of business is to check out the carb choke system and adjust it to work properly. That includes setting the 'fast idle' adjustment PROPERLY.
If set up properly, the choke plate will be almost closed off when you TAP (not stab to the floor) the accel pedal before starting a cold engine. And, once running, the idle speed should be in the 700-800 rpm range (without having to pump the accelerator before starting or constantly exercise it to keep it running). If it is running much higher than that, someone has increased the fast idle to compensate for a misadjusted choke. That would explain the excessive fuel fumes you are experiencing.
Curb idle adjustment screws should only be set when the engine is WARM. They should not be changed to deal with cold-start issues.
Cold start is about 1500. When I stab the throttle it goes down to about 1000. Once warmed up its around 650 700
It really shouldn't be above 700-800 at any time. Yes, when you set the fast idle speed with a warm engine, it is set at 1200 or so. But, when that engine is cold, it won't run at that elevated speed.
Yours is just dumping fuel into the intake when it really isn't needed. You need to set the choke up properly, THEN set the fast idle speed.
When you get the choke set right and the fast idle set right, you won't have all those nasty fuel fumes around you.
It really shouldn't be above 700-800 at any time. Yes, when you set the fast idle speed with a warm engine, it is set at 1200 or so. But, when that engine is cold, it won't run at that elevated speed.
Yours is just dumping fuel into the intake when it really isn't needed. You need to set the choke up properly, THEN set the fast idle speed.
When you get the choke set right and the fast idle set right, you won't have all those nasty fuel fumes around you.
I too replaced my old carb with a Edelbrock 1901.
I had bought one of those commercial rebuilds off Ebay.
That was before I knew any better and read Lars paper covering same.
It is on a 427/390.
Out of the box it cleared up allot of my problems.
I now have a working cold start choke, and good performance.
I like the carb too.
If you can take the time to set it up right and or rebuild it if due,
you will have a nice carb.
I'm sure mine could be dialed in specifically for my motor by Lars.
It is running well with no stumbling as it transitions into the secondaries. I've left well enough alone for now.
You can make this carb work very well for a street driven car.
Mine is dependable and for cruz nites.
I'm not looking to burn the tires of her.
Marshal
I have a 7029207 Quadrajet, Mint Condition for a 69 Corvette 350/350 horse,man trans.Would this be a better option for my 71? Even though it's an auto trans? The 207 has never been apart.
If as you said it has never been commercially rebuilt then it would be an excellent core to start with.
You could contact Lars and see if he is still accepting Qjets.
The only differences is the casting number and the throttle
cable connection. The auto has a place for the kickdown cable.
The 4speed would obviously not.
It can be rebuilt and configured to 4speed.
Cost about the same I'd imagine to have refurbished as the 1901.
Marshal
If having the exact, factory-specified carb on your engine is not a big deal to you, any Q-jet made prior to 1976 that is in good condition could be made to run just fine on your car. It's just a matter of knowing what to change in that carb to get it well matched for YOUR engine.
The 1901 carb is no exception. As long as it is working well, performance is decent (normal operation AND wot use), and you are getting decent mileage from it, there is really no reason to change the carb out. You just need to set up the choke and fast-idle correctly and you should be 'good to go'.
The complete setup procedure for the carb that came on your engine can be found in the "Engine-Fuel" section of the Chevrolet Chassis Service Manual for your model year. You can likely find that same choke setup procedure on the internet, if you search a bit.
71 carb. Question.
