Quadrajet idle screws question

[GXPWeasel]

I'm in the process of rebuilding my quadrajet carb, and during the disassembly phase, I'm ready to remove the idle screws. However, I'm not sure how here... These don't appear to be a screw that can be removed with a normal screw driver. See the picture of the diagram. It looks like maybe there are caps on the screws on my carb plate, but I tugged on them lightly with a needle nose pliers, and they didn't act like they wanted to come off.

What should I do here? I considered cutting a slit in these to create a flat head screw, and remove that way, but I'm not certain I can do that with these being so recessed as they are. And, I'm not sure that I should do that either.

thoughts please...

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[Bextreme04]

It's called a "double-d" head... it is the factory idle mixture screw. I would suggest replacing with these ones when you order your rebuild kit, they replace a 79-later "double-d" with a standard 3/16" hex head. https://quadrajetparts.com/idle-mixture-screws-2003a-metric-head-replacement-p-2624.html

 

[GXPWeasel]

It's called a "double-d" head... it is the factory idle mixture screw. I would suggest replacing with these ones when you order your rebuild kit, they replace a 79-later "double-d" with a standard 3/16" hex head. https://quadrajetparts.com/idle-mixture-screws-2003a-metric-head-replacement-p-2624.html

Well, too late to get them when I get my rebuild kit (already have that, and referencing which new gasket matches old as I remove them). I appreciate the help there with the link. That link brings me to the 79& later screw replacements (I've got an '82, but not sure if it's original).

The needles you don't show specifically they will work for my carb (17082224) but the description shows that they may work for others... If I look up my specific part # on the Quadrajetparts.com site, it doesn't show a needle in the 6 parts it listed. I ordered my kit from them, (the one shown when I put in my part #) and thus far it looks like a nice kit.

How do I remove the old ones? Just un screw with a needle nose pliers?

 

[Bextreme04]

Well, too late to get them when I get my rebuild kit (already have that, and referencing which new gasket matches old as I remove them). I appreciate the help there with the link. That link brings me to the 79& later screw replacements (I've got an '82, but not sure if it's original).

The needles you don't show specifically they will work for my carb (17082224) but the description shows that they may work for others... If I look up my specific part # on the Quadrajetparts.com site, it doesn't show a needle in the 6 parts it listed. I ordered my kit from them, (the one shown when I put in my part #) and thus far it looks like a nice kit.

How do I remove the old ones? Just un screw with a needle nose pliers?

yeah, or buy a "double-d" carb adjustment tool/bit

 

[Bextreme04]

you'll need to adjust them on the car once you get it rebuilt and installed anyways, so you need to either replace them or pull them out with needle nose pliers and cut a flat head slot in them to use a screwdriver. My '80 has a slot cut in the factory double-d heads and is a pain in the ass to adjust. I'm replacing them with the hex head or I would have bought one of those flexible screwdriver carb adjustment tools at the parts store that comes with the double-d bit for the end

 

[Bextreme04]

Link to tool that had double-d tip included.

\https://www.napaonline.com/en/p/BK_...9aqn8nIDo8Tr2Aovt0FJay5W21WxP2UaAplWEALw_wcB&

 

[GXPWeasel]

Yea, I had planned on removing them all the way (counting the turns to be safe) and using the linked video in the Quadrajet rebuild thread to dial it in initially before install. Then finish dialing it in after its on the truck.

Cool, well it sounds like I have some options.
I appreciate the help and quick responses Bextreme04.

 

[Waylon]

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I built this many years ago when I had a carb with those screws. I don’t remember why I cut the hex head off. Seems like it would be easier to turn if the hex was still there.

 

[75gmck25]

My rebuild kit came with new hex head idle mixture screws, but I wish the heads were a little longer. They are tucked up under the ridge left when they cut off the original tamper-proof screws, and you have to get your head down low to see them. Not the best angle when the engine is running and your head is right down against the top of the fan shroud so you can see the screws.

If the hex screw heads stuck out a little more I could see them easier and a 3/16th socket would fit. Now there isn’t enough clearance for a small socket because it would need to be long but have a very thin wall. A screwdriver works (they also have a slot in them), but it’s like fishing in the dark. I usually look at the screw to see the orientation of the slot, and then turn it and make another visual check because doing it by feel is difficult.

I’ve been trying to fine tune the idle mixture on my carb, so this is more of a sore point right now. My original ‘75 Quadrajet did not have tamperproof screws, so the idle screws were completely in the open. Much easier to see and adjust.

The Thexton tool used to be the most common double-d carburetor adjusting tool, but it looks like Lisle also has one now.

Bruce

 

[newguy11]

How do I get the damn plugs out?

Here is what I did.

I used a drwl with a cut off wheel to make them flat I then used bit 953 to patiently remove all the metal in a circular pattern. Once through I switched to a 941 cone bit to bring the taper all the way to the walls.

Patients is mandatory, results may vary

 

[Bextreme04]

How do I get the damn plugs out?

Here is what I did.

I used a drwl with a cut off wheel to make them flat I then used bit 953 to patiently remove all the metal in a circular pattern. Once through I switched to a 941 cone bit to bring the taper all the way to the walls.

Patients is mandatory, results may vary

Nice, most people aren't that patient with them and they just hack the bottom off. Now you just need a nice flexible carb adjustment tool like this one: https://www.napaonline.com/en/p/BK_...Pm8kmW4bXpJzHe-mXBoCcwwQAvD_BwE&gclsrc=aw.ds&

You can get a similar one for about the same price at just about any major auto parts store.