brianw

I'm new to the rotr but have basic mech. knowledge of how they work. Ive just bought a 83 and man if I was as rich as it's running I'd be replaceing the whole motor!
can anyone help?

Sterling

We need more info to help you...are you talking about just the idle, or all through the rpms, or what? Any history you can give will help, too.

Welcome to the forum and the wonderful world of "Hummmmmmmm..." and "Zoom-Zoom"!

XLR8

iTrader: (52)

Might be a float sticking. I would take off emissions equipment, plug with vac caps, rebuild the carb, new cap and rotor, etc.

Welcome to the forum.

brianw

Thank you for a speedy reponse.
It idles rough at or below 3,000rpm. It also is loading up at those rpms. smells rich at idle and I have some black smoke at start up which turns grey then ends after aminute or two.

Sterling

What do you mean by this?

The idle indicates a vacuum leak. The black smoke indicates oil presence at start-up. Treat them as two seperate issues.
Once you track down the vacuum leak and remedy that, and retune your idle, then you need to do an ATF treatment.
A write-up can be found at mazspeed.com or by searching here.
Do NOT do this untill your carburetor problem is cured.

brianw

Yes, I found a vacuum leak, when I spray carb cleaner at the back(firewall side) of the carb it idles up. Ia sume this is in the plate gasgets or are there lines back there that I can't see without taking alot of stuff off?Are these carbs hard to rebuild. This is ny daily driver and I don't have a spare carb to play with. Can you tell me where to find some DETAILED info on how to rebuild?

Sterling

Is everything still hooked up emissions wise? There is a 1 inch OD rubber hose that is a usual source of leaks.
It's hiding way down low, under the brake booster vacuum hose. Goes to from the ACV.
...they are easy to rebuild. Just clean the whole thing off really well first, and approach it like a surgeon.
Take your time. It's all very self explanatory once you have her opened up.

All that **** you see on the outside?...Well that's the worst part of it. The inside is cake compared to that.
Take pictures with a digy cam if you can. That way you can just look at how everything goes back together.

Look for "Carburetor rebuilding tips".

If you're worried, get a used carb from someone/yard to rebuild.

brianw

as far as I know eveything is still hooked up. I bought it from a real wanabe mech. so hwo knows what he did before I got it.I'm going to check the the booster hose right now.
Where can I buy a rebuil/modify kit? I figure if I'm going to rebuild it I might as well do some performance mods while I'm there.

inittab

Nikki Carburetor Rebuilding Tips

brianw

Found a hose directley above the booster hose on the block. About 1" OD comes of a flange goes nowhere and is not plugged. Obviuosly this is a problem. Where should it go? can I just plug it? Finally what is the ACV?
Bear with me I'll get the names of all this crap down but it may take me a minute or two.

inittab

Is the hose on the passenger side towards the back and down by the intake manifold? If so, that's anti-afterburn hose and YES, that will royally screw up your idle if disconnected or punctured.

brianw

Can I plug it? If not where do I hook it back up. That is where it is located. That has to be it.

inittab

I don't have a detailed picture of where it goes but it's a molded hose so following it should lead you to the right locations. Sorry I can't be of better assitance. Good luck!

slashdawg00110

The hose goes to the rearward-facing side of the anti-afterburn valve. The AAB is located at the top rear of the carb (if it's still there). It looks sort of like a brass top-hat. The AAB has 4 nipples for hoses to fasten to. One large one and one small one face the rear of the car; same for the front side. You need to attach this large hose running from the intake mani to the large nipple on the rear of the AAB. Be sure to check the bend in the hose at the intake mani end. The hoses often split there. Hooking up a split hose won't do much good.

If the AAB is not present anymore, just plug the intake port with a plug. IIRC, it's 1/2" ID.

brianw

Thanks!! That did it. I just got back from driving it after I pluged it and that made a HUGE difference alone. Now I can't wait to go look for the AAB. Thanks agian.
I'm new to This club, How do I post a pic of my car?

inittab

awesome!

In the upper right of your screen there's a tool bar with an option for FAQ, in the FAQ are instructions on posting attachments, here it is:

https://www.rx7club.com/misc.php?s=&...=3#attachments

brianw

Where do ypu set the idle? It still idles too high.

brianw

I'm not too sure about this going to the carb, the out let is cast and clearly pointing down.