Adjusting stock carburetor question.

Looking for a guide to the proper way to adjust a stock carburetor, I mentioned in another thread that the only way I can hear a difference is turning the long screw. The other two screws (or at least one) have to be doing something, just haven't ever messed with a carburetor. Also, the pin that's supposed to be blocking a screw is broken off, no idea how far off the previous owner might have turned that thing. How do I start adjusting this thing to make sure it's running right?

I attached a picture, the only screw I turned that seems to be doing anything is the green one, blue one doesn't seem to do anything. And the yellow one looks like whatever it's on is loose, I sometimes see it like kick back and forth and sometimes just shakes around when the engine is idling a little rough. Besides the green screw I haven't really messed with it much since I don't really know what each one is for.

I was also looking in another thread that a lot of the vacuum and emission stuff aren't needed for the truck to run, but if all of that is removed will it still be able to pass inspection? This is a '88 B2200 so I guess it already counts as a classic, or will that be next year?

Blue is your idle mixture adjustment. You need a dwell meter to watch the computers command of the air/fuel ratio to properly adjust it. It will affect your emissions at idle if it is off far enough. The green is your regular idle speed adjustment, don't know off hand what the correct idle speed is, but IIRC it is somewhere around 700-800 RPM at idle warmed up with all accessories off. The yellow screw I believe is the cold idle speed. So when the truck idles up when cold with the choke, that is when you would set that screw. Someone correct me if I am wrong.

The yellow is the A/C Idle Adjustment Screw.......it helps set the idle slightly higher when the A/C compressor turns on. That vacuum diaphragm right near it with the vacuum hose hooked to it will receive a vacuum signal when the A/C comp. is turned on and it pulls the throttle linkage by however much that adjustment screw lets it........now, if that screw is tightened too much, when the A/C comp. comes on, the idle will rev up, then down, then up, then down.....back and forth. All you have to do is loosen the screw a bit and it will quit revving up and down and stay at a constant rpm. If that screw is too tight, the vacuum diaphragm isn't large enough to hold the throttle opened that much so it will pull and release, over and over again, causing the idle to rev up and down.
You want to adjust that screw while the A/C compressor is engaged and on.
Here was a well used/known pic on that other Mazda truck forum!

I know that on the J.Y carburetor I bought, I removed the roll pin and then I counted the # of turns.,, for a total of 2 and 1/2 turns out, on the blue screw that earl circled for you.

Also, I bought a stock carb.rebuild kit, online..,from Advance auto, for a good price. Then I bought the Berryman chem tool cleaner 1 gal. at Walmart.

What an improvement!!!..,, after the clean and rebuild. Lot's of power,and I still haven't found top speed yet. I chickened out and shut her down at 98 MPH,because it was a windy day.

Good luck with that, and I gotta say, I am glad that I stayed with the stock carb and emissions.

Looking at this guide looks like I need both a tachometer and dwell meter? I got an all-in-one thing (tachometer, dwell meter, Voltmeter), guess I will just try and find where I'm supposed to connect this thing and see if I can get it to do something.

Where do you start with the screws though? All turned to the left as far as it can go?

EDIT: Is there any place to connect one of those ODB2 cables? I got one for my laptop on my other vehicles, but they all have the plug like under the steering wheel. Can't find one on this truck.