I need to know the idle control screw and the mixture screw.
 

my car idles @650rpm or so i think would need to be more at 900 to 1000rpm and i want to adjust the mixture so i can get some flames going.help a brother out if you have some pics.thanks. any fellow rx7s people located in Sacramento,CA?

Your car should be adjusted to750, not 900-1000 rpm, first of all.

Second, mixture screw only changes mixture at idle, i.e. up to about 2000 rpm.

Are you trying to find out where they are?

idle screw

https://www.rx7club.com/attachment.p...chmentid=88536

yeah. i dont know where to look. please attach picture if possible

mixture screw:

https://www.rx7club.com/attachment.p...chmentid=88537

What!?!?!?!? So you are saying that I can fck with my mixture all I want and after aprox. 2k rpms it doesn't matter?

You serious? if so,

Hi Neo, welcome... to the real world! :rlaugh:

After 2K or so, the jets and air bleeds are what affect the air/fuel ratio.

cdrad - nice pictures, very clean nikki.... but why in god's name is your return line capped?! And a brighter colour arrow would help in the first one. I *know* where the speed screw is and still didn't see the arrow!

Jon

I like to do things differently ;) seriously, it's a long story, but basically the capping of the return line was recommended by rx7carl on my particular setup, and it works perfectly.

On the arrow, just get a better monitor man :D

I know what you mean. When I was making that arrow I thought it might not be too clear and was thinking abut making it white instead but then thought nah, he'll find it. Eventually.

Yeah, I was gonna say- that cap-job aint my work! :P:

Show the dude a piture of the idle SPEED screw. He starts messing with the mix @ 650, and he'll be plaguing you with questions about how to fix it!

Yeah, cp- 1.8K and kiss the mix screw goodbye.
Why, you idling like batshit?

Dennis! long time no flame! :p:

Idle speed screw pic is above the mix screw. Open your eyes old man!

I think I saw a thread or a write-up somewhere that also covered the capping of the return line with a similar setup than mine. Don't know why, all I know is that it was the only way I could get 2 1/4 - 2 1/2 psi in the FPR's gauge.

P.S. btw, noticed I got rid of the valve the AP rod used to rub against? much cleaner setup now.

Yes... the longer AP rod rubs against the useless shutter valve... I didn't notice it at first and had hella trouble starting the car without the AP shot to help me. Out came the shutter, in went the JB QuikWeld, and boom, instant cure for starting problems :)

I think the Rx7Carl/Sterling carbs should come with a big paper sign saying "Don't forget to remove your shutter valve - it's more useless than your appendix!"

Dennis, we still on for spring? I'm lookin' forward to tuning this baby ;)

Jon

Well.. I decided that since I nicely contributed to jacking this thread, I'd make a post helping out sketcher:

To bring your idle speed up, you want to use the "idle speed screw" which basically pushes on the linkage, setting it's stop point. By screwing it in, it's the equivalent of very lightly holding your foot on the gas, bringing the idle up. On the 79-80 carbs I believe the "idle speed" screw was an air bleed screw situated right above or below the idle mixture screw (can't remember which).

The idle speed screw you're looking for is the first one that was posted in this thread. It's a bugger to find if you still have your rat's nest installed, but a long handled flat screwdriver, some patience, and a good flashlight will help. Screw in to increase base idle speed, screw out to reduce base idle speed.

You want to turn it in until your idle reaches between 750-1000RPM. The shop manual says 750, but I like mine idling about 900-1000. I guess with all the idle problems I had when I first started working on the car I just don't trust it lower than that ;)

Once you have it idling high enough, you can play with the "IDLE mixture" screw, which contols the mixture at idle. IIRC it's turn in to lean, turn out to rich... but someone could correct me on that. You want to turn it "lean" until the car hunts a little, then turn back out a bit. I think the shop manual says half a turn back, but I don't have it on me. If this changes where your idle speed is at, you can adjust the idle speed screw again.

Bounce back and forth between these until you have a car that's idling steady around 750-900 that isn't running too rich.

Now the carb experts can flame me for any little mistakes I made ;)

Jon

Edit: I re-drew the arrows in the pictures so that they show up better. Here ya go

Just busting on ya; if it works & it's clean, well it's good, right?
Good job on the fart-valve.


Yeah, Jon- We're on.
When everyone else counts down to midnight for newyear's eve, that's when I start the countdown till nice weather!

I'm gonna get Tom back up to this neck of the woods, too.

Waitaminute.. splain more why the return line is capped in that picture?

dale

Hell all. My car idles at around 500-650rpm, I want to adjust the idle on my 84' GSL, but all I can find is the mixture screw on my carb (small phillips head). Where's the Idle screw? My 82' had them one above the other. Nothing seems to be missing. Though it's kinda tough to see through that rats nest. Is it the one to the far right like in the pic on the 1st page of this thread?

Yes.

i got the idle at bout 1100 i dont know it just sounds like its happy there. i wanted to know when you know when your too rich or lean?

Which should i adjust 1st? The idle or mixture? I just read the Haynes manual and it says to diconnect the richer solenoid valve b4 adjusting the carb and readjust the throttle sensor after.:confused: Damn is that all necessary? I need to get all this smog equip. off my car. LOL

Oh well can't help you there all my emission crap is gone lol. But the idle should be under 1000 rpm. If you can't idle normally under 1000 rpm you have a vacuum leak or an ignition problem.

You're too lean when you screw the mix screw in and it starts to want to stall. Then you turn it out 1/2 turn out or so and that should be good.

750 Rpm.

Yes Dennis, seven hundred and fifty rpm for a 12A.

"...If you can't idle normally under 1000 rpm you have a vacuum leak or an ignition problem."

(Sorry, If I am high-jacking the thread, but this hits so close to home!)

I think my "hunting" idle is due to an ignition problem, then. It hasn't idled correctly in a long time, even before my carb rebuild. This rough idle prompted my carb rebuild.

I've adjusted both the mixture and the idle screws, and my idle "hunts" (Translation: Rrrr...Rrrr...Rrrr...Rrrr...Rrrr)

I've also noticed a noticable bucking when cruising at around 2,500 RPMs, without acceleration; almost as if the "hunting" idle condition is creeping up into that RPM range. It accelerates nicely, but when I am cruising with just the slightest bit of gas without accelerating it has some "bucking"going on.

I've rebuilt my carb, changed spark plugs and changed the fuel filter.

I am thinking of getting new coils, next.

Well, have you looked for vacuum leaks? and have you checked timing?