Quadrajet Carburetor Choke Adjustments are the best way to get instant starting, drivability & MPG! 

Out of all the videos and posts I've perused looking for answers, this is the only video that actually explains the purpose of the set screw on the choke pull-off and how it pertains to pulling the air door open a crack when vacuum is applied to the pull-off. I had my choke set all wrong, hard starts, funky idle, just because the pull-off was so loose it did nothing. 👍. Thank you, seriously.

Ok. This is the BEST choke video on RU-vid bar none! FINALLY....someone who FULLY explains (in sequence) of how these quadrajet chokes work. Very good, thorough, chronological description of what happens. I was able to follow along and understand the steps as you presented them. I'm not new to carburetors, I've run plenty of Edelbrocks and Thermoquads. I'm just now learning how Quadrajets work though. Thank you. I also didn't draw the connection of how the fast idle speed goes up if you do not release it with a tap of the pedal. I learned something today! Thank you AGAIN! No slam here, but Thermoquads are much easier to deal with. I know they get a bad rap, but both the fast idle and idle screws are basically on top of each other on the same side. Super easy to deal with. no bending down with a flashlight to find the fast idle screw when it's on the car. No special idle adjustment tool (my Qjet screws are buried in the baseplate). They are just out there in the wind up front easy access on the Thermoquad. You don't even need a slotted screwdriver, the needles are knurled. Easy of use goes to the Thermoquad.

Thank you for your service!! You just gave me a major education on the three phases of my Quadrajet choke!! Great instruction and heartfelt. Keep doing what your doing Sir!

Glad to see your back

The primary function of the front "choke pull off" (secondary air door dampener) has very little to do with the choke. Its primary function is to regulate how fast the secondary air doors open so you do not get the lean bog when you put your foot in it. Without that dampener your quadrajet will run like crap when you try to give her the beans. Many, many shadetree mechanics have made this mistake and thats why the quadrajet has a bad reputation and nicknames like "quadrabog".

Great video, now I can try to set the choke and fast idle on my '83 Toronado.

if this video doesn't help your Q Jet roar like a lion then I don't know what will!!!Good Work Sir

This vid is amazing & SPOT ON!!! And it even has a Square Body truck in it too! BONUS!! 😁😎🤘🏻

great explanation. Know need to try and adjust my Nikki four barrell

Good video thanks I appreciate the break down.

Applying this to my mercruiser quad

Hmm Buick motor in the Diesel Suburban thanks for sharing with us on the Q-jet adjustments

It has been many, many years since I played around with carburetors. I just could not get my 1976 Eldorado Convertible dialed in with the cold idle. Taking a few minutes and watching your video was a game changer. Watching exactly what each of the mechanisms do helped me understand again how they need to work in concert with each other. I immediately went out and made those adjustments and it worked the very first time. Thank you for your video. I do however have a question as I just can't remember. When the car sits for more than a few days it takes a lot of cranking to pull fuel. I initially thought that I was leaking gas out of the bowls and it would take time for the cranking to work the pump to refill them. This is a new carburetor and indeed I can start it with in a few days with no problem, but anything over 3 days has to crank quite a bit to bring fuel from the tank. Any ideas?

You got a like and a subscribe just from your name HAHA that and holy cow your one of the only people to cover a quadrajet caarburetor!

How do I adjust mine when having an issue with every time I press the gas when idling it forces the carb into a high file?

Great video. My 78 Cadillac Coupe with the 425 runs like crap when starting from cold idle. I do the one pump and itll start but will run awful. However once its warmed up and used during the course of the day, she'll run perfectly fine. I should point out, last year i did not have this issue at all, so i wonder what could have started the issue this year. Im in west Texas so our winters here are not like super cold. Usually in the 30s unless a cold front passes and dips our temps lower. Anyhow, any input would be appreciated. Thanks

So that high idle screw isn't just for the cold start? It affects idle for the entire time? I didn't like how high it was running at cold starts so I turned it left 2 times. Fixed my problem but now she's running really lean and diesling!

Thanks

I have a business rebuilding carbs and the one thing I find kinda funny and irritating at the same time is that both my 77 k20 and 85 k10 suburban with their factory original q-jets, will start every time with no issues clear past -40 degrees and my 98 s10 with fuel injection won't start when temp is in the single digits in the positives... and my suburban I use rottella to 15w-40 all year here in montana

Thats what I run in my Olds 350 Rocket...Rotella T6 5w40 in the cold and 15w40 in the summer...I'm having a hell of a time with my quadrajet in my 1978 Delta 88...doesnt want to start at all in the cold without starting fluid and in drive it idles very low...I just got the car and I dunno what the hell the guy did to the thing...I'm hoping the weather will get better so I can go outside comfortably and get her dialed in right.

Lets put it this way, my 71 VW is fuel injected and I can't climb the driveway in second gear...I'll use this info on the quadrajet converted mopar rv

Hey buddy. My 83 cutlass starts up great when cold after pumping the gas 5-7 times. Drives smooth with zero issues but after shutting it of to go inside a store, it doesn’t want to start. I have to take the air cleaner off and hold the choke open with a rag while I turn the key and starts up. Why does the choke close so fast? Is my electric choke bad or something needs adjusting?

Very thorough video, thank you. I have a question though. My '86 Caprice with the electric choke starts right up, but then idles very high, and stays there for almost 5 minutes before the fast idle will drop down to a lower step. To reach the lowest step (curb idle?) it takes almost 10 minutes in total (!). Once it gets there, it seems to run pretty good. This is in cool temperatures, but not freezing or anything. I believe my choke and choke pull off are set correctly. What could cause this? Is it the high idle cam being too tight perhaps? You'd think that, with such a high idle for 5+ minutes, it should come down easily, but it won't for some reason. It makes starting up the car pretty darn stressful.

I bought a brand new 76 Trans Am with that piece of junk on it. I never stopped working on that carburetor as long as I had it. I drag raced and I have worked on many carburetors so believe me i knew what I was doing. I was constantly adjusting that choke. The only way that I finally fixed it was by adjusting the choke door to where it would the best, and then I took a hammer and a screwdriver and taped a little dent in the choke horn so that the choke door would not be able to move. I never ever had any more trouble out of it. That was and is by far the worst excuse for a 4brl carburetor that was ever made! My float bent! I had never seen anything like that happen before. I just to let you know! It wasn't because of bad maintenance. I kept that car for 18 years, and when I sold it, it almost as good as new. My advise to anyone who has this piece of junk on their car, is to take it off and throw it in the trash! I finally replaced mine with a 650 Holley spread bore and it totally changed that car for the better.

The reason i duslike modifying, is it changes all the perimeters, meaning you can't use factory settings, and it wont run like factory, whech was really really good. 3.5 turns out on air mixture screws, 2.5 on apt, high idle set at 1900 rpm. Idle speed set at 700. Both those set the proper throttle plate angle. Thats really important

Howdy - My question is about other items I noticed in the video that I am interested in. 1) What type of guages are those in the dash and where did you get them? 2) What is that fuel line with the filter on the drivers side of the motor? o you have any videos on these items? Great video and very useful information. Thank you

I have a 1984 g20 with a 305 and quadrajet, this is my first rodeo with a carb but I'm trying to learn. Once it start my van it will idle high for about 8 minutes before pressing on the gas will kick down the high idle to a normal idle. Not sure where to start, no matter how much I press on the gas the high idle won't kick down until its ran for a good while.This is usually only after the van has sat for at least a few hours. Any advice where to start?

My dinosaur has ben eating holley's for lunch for 40 years now !

What vacuum should the front vacuum break allow the secondaries to open? Mine seems not to let them open even as low as 14"???

Normally if the choke is still at factory settings it's best to not move anything ,those rods get bent or changed its ruined ,

Great video bud!! I got a problem on my 72 vette my rochester needs at least 6 or 7 pumps to start??? What's my problem??

I have notice our fuels are not working like they used to I had to finialy put a pressure regulator on my q jet to 3 lbs flooded with 6

excellent! Is that a pontiac engine?

What's that pipe plug on the air horn? Midrange adjustment. You do video on that someday?

My choke doesn’t snap like yours did when you gave it one pump. It doesn’t move at all….?

Its just like with thermoquads . they work great as long as you do the basic up keep on them and nobody before you messed with all the different settings

Have you ever had a manual choke quadrajet?

My 83 caprice high idles for 5 minutes because when I give it throttle it won’t lower the rpm until 5 minutes and it’s completely warmed up

What if my rpm doesnt work

My electric choke heater is connected to the hei power.

I was wondering what Woody Harrelson was up to these days

I need my 1969 Cadillac coupe deville started I hope you can help me plus I am will to pay you if you are available

...is this the same as "flogging your dolphin?"

I think you were lean

I'm lost.

I stopped ckoking my dinosaur when I was 15.

What is this about? a lot of blah about adjustments and the just adjust the idle speed and talk about an engine warming up?

They were not hard to set up. Really easy. You younger people are not used to carburetors. They were not that mysterious.

Why do bloggers present useful information that is masked by background noise? It's effing stupid. Turn the damned fan off next time!

I did not appreciate the long discussion on history and comparison to fuel injection systems. Maybe take your comedy routine elsewhere. Rochester choke adjustment is not difficult. I stopped watching halfway through because I couldn't see the value in watching any more.