What screw is this?
 

I am looking at a throttle adjustment picture for a 1985 RX-7 with carburetor (12A), I can locate the throttle adjustment screw; but, am wonder if the screw directly parallel and to the left is the mixture adjust screw? Page 74 of a Chilton repair manual or page 263 of a Haynes repair manual.

hmm, the 1st gen carb motors I have seen, when looking directly across the engine from the left, umm your drivers side, at the base of the carb there are 2 screws. one big and one small.

the large screw is the idle speed, and the smaller screw is for the mixture setting. but this is for australian models, so it may be different for US spec.

I cant actually find a 'conventional' throttle scrwew, ie. one that moves the throttle butterflys...

I beleive the mixture screw moved to the rear facing side of the carb in later model year. Idle screw is bigger and slotted, mixture, smaller and Phillips. I think that remained constant, at least.

this screw on mine was on the front side of the carb BUT u have to take the carb off to get to it because it right on the bottom...

Here in the states it does depend on what year. I've never actually seen an 80 or older carb, but I think the screws are in different places than the later carbs...Which I believe are then all the same.
On my 85 Nikki, the idle adjustment screw is hidden under and behind the primary shaft linkage on the right side of the shaft. This is facing the carb from the drivers side fender (in the states!). You have to contort yourself just to see it, let alone adjust it!
The mixture screw is directly in the center of that side of the carb, but a bit higher up than the idle screw, But it's covered with a potmetal cap that's crimped. This is because the emissions control system is so specific- IE, it works ONLY when everything is ABSOLUTELY perfect. So they put that tamper-resistant cap on. Just pop it off with some care as not to be too rough on the mixture screw. The threads are fine, and the point is delicate.


I hope I helped. Keep asking if not, cause others here know for sure.

air/fuel mix screw is closest to front of car, idle screw is towards windshied ,and get a flashlight and look under the accelerator pump for the screw...

air mixture screw
 

directfreak-excellent visuals...answered my question perfectly...thanks for your assistance!!

Re: air mixture screw
 

No prob. A pic is worth a 1000 words.

To confim the post above concerning pre '80 carbs, my '79 has the screws mounted on the drivers side of the carb, towards the firewall. They are in a vertical line, with idle speed on top and mixture on bottom. The speed screw is large and the mixture is small.

Matt
1979 SA22C

Hey, DF, that site is down, you know if it exist anywhere else on the net? I'm trying to locate the damn A/F screw.