1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

which is the idle adjust

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Old 06-16-08, 10:04 PM
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which is the idle adjust

just wondering which of these is the idle adjustment screw, my idle is a bit high and i want to get it down a bit . i know the air fuel mixture is right next to the idle screw and i dont want to mess with that and **** up my cars
Attached Thumbnails which is the idle adjust-idle.jpg  
Old 06-16-08, 10:05 PM
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is it the big one or small one under it?
Old 06-16-08, 10:08 PM
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download FSM in my sig, as well sterling has a few good tutorials.

Cant help you as my stock carb looks nothing like yours for some reason
Old 06-17-08, 06:35 AM
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ya i was comparing my stock carb to this turbo prepped they are different
Old 06-17-08, 09:35 AM
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i know my idle adjustment screw is right out of sight under the bracket to the right of the mixture screw


the bracket with the red arrow on it. underneath there. you might have to get your face down there to actually see it, but that's where mine is.
Old 06-17-08, 11:35 AM
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Originally Posted by rotary84
is it the big one or small one under it?
you have an SA carb, its both
Old 06-17-08, 01:15 PM
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Big is air, small is fuel for idle mixture - together these can adjust idle speed. The screw to the right is the throttle stop/idle adjust - this too can adjust idle speed but shouldn't be used specifically for this purpose.
Old 06-17-08, 01:22 PM
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Originally Posted by Jeff20B
Big is air, small is fuel for idle mixture - together these can adjust idle speed. The screw to the right is the throttle stop/idle adjust - this too can adjust idle speed but shouldn't be used specifically for this purpose.
jeff so when i adjust the small fuel for idle do i have to also play / adjust with the big screw to kinda even it out?
Old 06-17-08, 01:25 PM
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Old 06-17-08, 02:02 PM
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Originally Posted by rotary84
jeff so when i adjust the small fuel for idle do i have to also play / adjust with the big screw to kinda even it out?
You should only mess around with the mixture adjust screw when you overhaul the carb or after just installing a new unit to the car.

If it was correctly set after initial install you should not mess with it.

If you still have to mess with it because accidentally touched it or so. Just get the book for the carb you are using and find the settings there.

Rule of thumb is: (Stock carbs use this settings)

1. set the idle to 770 by using the throttle screw
2 set the idle to highest rpm by turning the MIX screw
3 reset the idle speed to 770 by using the THROTTLE SCREW
4 Then adjust the idle to 750 using the MIX

as you are doing this note wich way increases and decreases on both screws

Sometimes you have to adjust the throttle sensor as well but I have been lucky most times. This is pretty simple to do.

I hope this helps

I was just looking at the post and realized you are probably talking about a carb that I may or not be familiar with.

I apologize I can't see pictures when I am at work. They are all blocked, you know government computers LOL

Anyway good luck with your carb.

Last edited by Pocket Trey; 06-17-08 at 02:12 PM.
Old 06-17-08, 08:27 PM
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Excuse my sstupidity

I understand air & fuel, which do you mean when you say (Mix & Throttle ) ?
Thanx.
Old 06-17-08, 08:38 PM
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Originally Posted by slowpoke63
I understand air & fuel, which do you mean when you say (Mix & Throttle ) ?
Thanx.
The thottle is to your right as you see them. On the above pic is the red arrow.

And the mix is the one that can be easily seen or the one to your left.

People call them differently. I chose to use the correct term for them, but any name is all the same they usually do the same thing regardless if you call it fuel or air or any other name.

Im joking around with the name thing.
Juan

Last edited by Pocket Trey; 06-17-08 at 08:44 PM.
Old 06-18-08, 12:28 AM
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Originally Posted by rotary84
jeff so when i adjust the small fuel for idle do i have to also play / adjust with the big screw to kinda even it out?
Yeah, more or less. The later carbs 'deleted' the air screw and had it pre-set inside through an orifice of a factory-set size. They even attempted to make the fuel screw inaccessible by placing a silly cap over it, which must be pryed off. Lucky you to have full access to both.
Old 06-18-08, 12:28 AM
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Originally Posted by Pocket Trey
The thottle is to your right as you see them. On the above pic is the red arrow.

Im joking around with the name thing.
Juan
he's got an SA carb, its different.

you basically adjust the idle air screw until you're close on rpms, then the idle mixture, then the idle air, etc etc until you get a nice smooth idle.

go as lean as you can with the idle mixture, it has a big impact on gas mileage
Old 06-18-08, 12:29 AM
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Agreed. Those thermal reactor carbs had grossly rich idles to keep the fire lit inside them.
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