Quadrajet Question

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Oct 14, 2008
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I personally like the electric choke better, much more adjustable and less finicky for the correct setting. Just use something easy to remove when blocking the holes like RTV. I used JB Weld because I am never going back to hot air.
 

pontiacgp

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Mar 31, 2006
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Kitchener, Ontario
You are correct, but it is a controlled vacuum leak when connected to hot air coil. Brake booster is a vacuum leak also, but controlled as well. Not the same as leaving it open. All open vacuum ports should be used or plugged.
As I mentioned, you might possibly need to create some additional bypass air if you have a modified engine. Stock will probably be fine without needing additional bypass.

There is no difference to have the hot air tubing hooked up or not, the diameter of the hole regulates how much air passes, not the length of the tube. The carb was built with that air passage and the amount of air being introduced to the carb from that hole was in the design. Also it makes no sense if plugging it up causes a rich condition where you modify the carb to correct that.
 

pontiacgp

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Mar 31, 2006
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Kitchener, Ontario
I personally like the electric choke better, much more adjustable and less finicky for the correct setting. Just use something easy to remove when blocking the holes like RTV. I used JB Weld because I am never going back to hot air.

the thing with the electric choke is it's based on time and not the actual conditions, with a hot air choke on a colder day the choke stays on longer and on a hot day the choke shuts off quickly unlike the electric coil.
 
Oct 14, 2008
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Melville,Saskatchewan
True enough but there is a very small range where it will work correctly. Maybe it is the ultra lean mixtures on some of my cars and so many months with days below freezing or close to it here, longer choke time helps with the running. I have to say my 260 works quite well with the stock hot air choke. Plus the coil is stuck in place so I can't mess with it:). Maybe it was the pull off that needed adjusted on some of my cars when I was young. I just had bad experiences, including seeing rotted intake tubes, maybe Olds was on to something, they stayed with it to the bitter end.
 

pontiacgp

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Mar 31, 2006
29,270
20,391
113
Kitchener, Ontario
True enough but there is a very small range where it will work correctly. Maybe it is the ultra lean mixtures on some of my cars and so many months with days below freezing or close to it here, longer choke time helps with the running. I have to say my 260 works quite well with the stock hot air choke. Plus the coil is stuck in place so I can't mess with it:). Maybe it was the pull off that needed adjusted on some of my cars when I was young. I just had bad experiences, including seeing rotted intake tubes, maybe Olds was on to something, they stayed with it to the bitter end.

it all boiled down to reducing material and production costs while increasing the sale price......as usual

and now I'm trying to order a couple of air horn gaskets but my credit card is being rejected...gotta love technology....:(
 

Bonnewagon

Lost in the Labyrinth
Supporting Member
Sep 18, 2009
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Queens, NY
Actually I think the absolute best choke is the old divorced style. It has a choke coil mounted in a cover that is bolted to the crossover. Some had it in a shallow well. A rod connects the coil with the choke flap mechanism. Most old time manifolds had a machined pad with a tapped hole for the choke coil to mount on. My point is that when the car is cooling off the intake stays at the same temperature as the rest of the motor and the choke coil is always at the proper setting. Thus no matter what the motor temperature is, the carb starts right up. They haven't used that since around 1972 because of emissions concerns. I miss it. Also on the hot air choke, there should be a hose from the cold air intake side of the choke tube that goes to the air cleaner housing. That way all the air that is ingested by the carb through the choke housing has been filtered. It is less of a vacuum leak problem connected that way. That hose rarely survives and you've probably never seen it.
s-l225.jpg
 
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Quadrajet Power

Not-quite-so-new-guy
Oct 20, 2016
27
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3
Waring, TX
The hot air choke wasn't an open vacuum port. It was looped. Leaving it open creates a vacuum leak, which is why Cliff, myself and other builders recommend blocking all ports not in use.
 
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