Does anybody sell easy adjust mixture screws for IDFs? I can find them for other types of carbs but no IDF.
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The 'mixture' screws on my IDF's are knurled, spring-loaded thumbscrews that are pretty easy to turn by hand and readily accessible. They don't technically adjust the idle 'mixture', but that's a rant for another day.
Do you, by chance, mean the idle jet holders? Those are hard to get to when mounted in a Speedster engine compartment and made fussier because you need a (very short) screwdriver to remove them. There are hex head/allen key replacement holders that make the jets much easier to remove.
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Mitch is 100% correct, although in a Speedster it does make it difficult when the screws are facing the engine compartment walls.
I use a thumb/forefinger combo on the mixture volume screws(what Mitch was alluding to: the mixture is set by the jet itself, the screw adjusts the volume of said mixture).
I use a thick slotted stubby screwdriver to break the jet holders loose, and a thin-blade to spin them out. The fuel inlet on the carb top is right in the way. Don't lose the O-ring!
There are aftermarket(and better) jet holders that are available from JayCee. They are also available from other vendors but the prices are pretty high. You can use an 8mm box wrench on the outside or a 4mm hex key on them, which works best.
The lowest price is from the source:
I have a tiny, 1/4" finger-drive that makes getting to those screws a lot easier. Unfortunately, Lowes no longer carries them, but I found something similar at Harbor Freight that should fit in that tight space:
https://www.harborfreight.com/...set-18-pc-67973.html
Mine looks like this: Super handy little tool.
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Alternatively, you can braze/weld/silver-solder a screwdriver tip to a nickel.
I have an injured right had from a table saw accident. My fingers tips are numb and I have weak grip with that hand. I can turn them, but it is not easy. I have a thumb screw like the one above. I haven't tried that. It is a PITA to get the screw driver bit into the slot.
I just thought I ask to see if anyone has seen those easy adjusts for IDFs.
Yeah, finding the slot kind of sucks, and I get it with the numb fingers.
In my experience, the Dell screws are more difficult to turn and get to than Webers.
On Webers, I've always used my fingers to turn them.
You could weld/braze a bigger knob directly on the "mixture" screws, since they are made of some type of steel. Would that help?
Failing that, you could have a machine shop make you a slotted driver(similar to what Gordon uses) with a tube around the bit, super easy to find the slot when working blind. And large enough diameter to easily turn, even with numb fingers.
Or this:
Are the mixture screw heads on a Weber round and if so, can someone tell me the OD of the screw head? @DannyP? I may have an idea for an easy, self-centering tool but I’m still nooodling on it.
My Dells have a slotted mixture screw and I agree that the slot is often hard to find, blind, but the head of the screw is also a hex head, not round or knurled. I used to just turn them with my fingers and then later used a 1/4” drive socket on a finger ratchet. While that worked, using something that is locked (not ratcheting) is a lot better as you are dialing the screw back and forth.
That said, a blind screw slot is a major PITA just to get at, let alone keeping the driver in the slot. It’s high time we had a reliable, easy-to-use, self-centering tool to help do the job.
They're round, Gordon.
It would be great if they were hex like Dells, but they aren't. And they're a different thread before you ask.
I can measure tomorrow if you'd like.
Those little handwheels I posted the link to don't ratchet, they are fixed.
Really the best thing would be to weld or braze some nuts directly on the screws.
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If it mattered, one could always buy 4 needle valve/screws, solder brass nuts on them out on the knurled ends, and adjust them with an ignition wrench.
I like using the wrench on my DRLAs because I'm a ham-fisted gorilla, and using a wrench gives me a reference for how much I've backed out from the RPM drop point. A real carb whisperer doesn't need these crutches, but I'm an ape with tools.
A dime is fine, most of the time, as long as you can find that screw head line.... For me the tool of choice is a small, thin fender washer that I file a flat surface on and kept on the car's key fob.
Honestly, guys....... Brazing a screwdriver tip onto a coin is fine if you have a welding torch - Most of us don't and besides, ordering one of those little finger screwdrivers that Danny linked would be GREAT.
I found them on Amazon Prime with all three in a package deal with Prime FREE SHIPPING! all for $11 bucks. The shipping alone from Speedway for a single one was $18 to me. 🤬
I had problem finding the mixture screws and the idle jet screws. I needed to SEE them. My solution was to swap the carburetors so that the adjustment screws faced toward the center of the engine. The intake manifolds had to be replaced with Space Saver manifolds. This moves the linkage to the rear of the carbs. There was some machine work involved.
Now everything is easily accessible and you can see what you are doing.(This won't work with stock fan covers). Needless to say after making this change and finally getting the carbs balanced and adjusted I haven't needed to mess with them in years.
You will surely want to install the JayCee jet holders and jet doctors.
The easy adjust mixture screw looks like a simple bit of modification to the stock screws. Lots of good suggestions here. Send me the screws I'll make and fit the knobs.
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Yeah, the space saver manifolds won't work very well with a stock shroud. Works GREAT with the 911 shroud though.
I was thinking the same thing, Jim. Send me 4 idle screws and I'll machine some nuts and press them onto the screws. I have a lather with a small chuck for holding small parts. Piece of cake.
They're brass. Just soft solder them.
Weber idle screws are NOT brass. The old Italian Webers come with hex-headed screws, the Spanish ones come with knurled round knobs.
That's why I suggested a drill and friction fit of a nut. Braze would work though, or even JB weld.
That's a refrigerator magnet they're on.
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Ah. I'll just go back into my hole.
Just a thought, but what about wing nuts? Adjustment would be stupid-easy.
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We really should put Gordon to work on a stepper motor controlled screw you could adjust from the driver's seat.
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"I love it!"
But it's gotta be bluetooth wireless.
Incredibly helpful as usual, Danny.
@Gordon Nichols posted:"I love it!"
But it's gotta be bluetooth wireless.
Oooo yeah! Write an app for your cell phone and do it from there.
@Lane Anderson posted:Oooo yeah! Write an app for your cell phone and do it from there.
That's called EFI...
I love the idea of servos to adjust the mixture and jetting on a carb according to some barometric, throttle position and O2 meter readings fed to/from a phone so you could watch the screen and interfere. I want this to be immediately devised, documented in a three-page instruction manual printed on broadsheet newsprint in 10-point type, crated in wood and shipped to Stanistan.
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It's already available online, with some reported QA issues:
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@edsnova posted:I love the idea of servos to adjust the mixture and jetting on a carb according to some barometric, throttle position and O2 meter readings fed to/from a phone so you could watch the screen and interfere. I want this to be immediately devised, documented in a three-page instruction manual printed on broadsheet newsprint in 10-point type, crated in wood and shipped to Stanistan.
Kinda reminds me of the instructions that came with a WiFi compatible door lock I bought off of Amazon:
It came with a Double sided, 8" tall and 39" wide set up and instruction set printed at maybe a 6-point font (hard to tell) with illustrations, it was a thing of beauty.
And it was all in Chinese........
Since you guys are all SCREWED with carburetors, let's get back to the original post.
I don't have a set of the EMPI HPMX "Weber clones" but as I recall they have round-head idle screws. Anyone verify if they're steel as well?
I have the HPMX they are steal. Tested with magnet
@Gordon Nichols posted:Kinda reminds me of the instructions that came with a WiFi compatible door lock I bought off of Amazon:
It came with a Double sided, 8" tall and 39" wide set up and instruction set printed at maybe a 6-point font (hard to tell) with illustrations, it was a thing of beauty.
And it was all in Chinese........
Ok, Gordon, you've got me snorting up orange juice onto the keyboard AGAIN! 
As I was getting ready to go to Central America with a medical organization in 1967, they taught us how to give inoculations by injecting water into an orange. It seemed a lot more practical than practicing on a real person. 🙄
We quickly realized that shooting Vodka into an orange instead of water was, by far, more interesting and fun. Try that in your Orange juice - It's 5 o'clock somewhere.....
@Gordon Nichols- We've done that- it works with watermelons too.
And I only put rum in my orange juice in the mornings 3 weekends a year...
This may have already been mentioned, if not, this may help some if their cars fitted with 911 stye fan shrouds. I don't know if they're still available, but I found a set of manifolds that turn the IDFs around so the mixture screws face inward. Required some linkage imaginings but doable with minimal harsh language. Sorry can't be more specific as I did the mod back in 2005.
CB makes the Space-Saver manifolds for IDFs that turn the carbs around. If you order the linkage from them, it works with no modification necessary.
They will fit with a regular VW shroud, but #2 or #1 idle screw is partially blocked. These manifolds are best used with a 911 shroud, as Jim Gilbert, Ewatub, and I have found out.
I didn't order them, but Jake Raby chose to equip my engine this way, and I'm glad he did. Now that I did EFI, the fuel rails are toward the INSIDE, away from the frame rails that they'd surely be up against with regular manifolds.