How hard is it to rebuild the stock carb on an 85 12a.
I have no previous carb experience but i have replaced the engine, transmission, radiator, brake calipers, pads rotors, put a limited slip rear end in my gs, shpcks struts, and all new steel braided brake line and bent some steel ones for the rear. So i do have a bit of mechanical knowledge but not with carbs neer took one apart??

I had her runnin with the new engine but not at low idle. now she wont stay running for more than a few seconds? I think its the carb ... maybe the accelerator pump? thats what ive been reading on other threads. Or a vacuum leak? Bad gasket? someone help me out if you can?

Thanks

Josh

 

I don't know how hard it is, but the 1979-1985 mazda rx7 haynes manual describes how to do it.

 

When I first looked into rebuilding the Nikkis, read the Haynes and FSM, I said no way. Too damn many parts, lol. In fact, I rebuilt an engine before I tried a carb. I now have forum members driving up from KC for rebuilds. Take your time, get organised, have a large clean work space and download the online carb manual in the archives. With all the other work you've done on your car, you should be able to get through a carb rebuild.

The last kit I bought from Autozone was a G P Sorenseen kit, it's a good kit with the aluminum washers. If you don't have one, pick up an impact screw driver, (manual, not air), it will save a lot of stripped screw heads.

 

I rebuilt my carb about 2 years ago with the Haynes manual. It really was not too difficult. Just make certain that your floats are adjusted correctly before you put it back together and that your work area is clean.

 

The Nikki on my '83 is the first carb I ever rebuilt. I used my digital camera to take pictures of the carb from every angle before I started and then loaded them onto my laptop when I started to put it back together. That helped get all the pieces back in the correct place. Oh, the bolt in the center of the carb that the air cleaner bolts down to holds the top of the carb on. Unscrew it first. That stumped me for awhile (until I read the manual!). Good luck!
- David

 

thanks guys! i might just give her a shot if i f it up oh well its only like $24 for a rebuild kit. by the way i work at autozone

 

I rebuilt mine with just the haynes manual and the parts diagram that came with the rebuild kit. Not hard at all. You just have to keep track of everything. A compartmented box and/or a lot of zip lock bags work well. I used an upended foot stool that had a very nice honeycombed pattern in the bottom. It had about two dozen nice square boxes. Label each box or bag too. Whatever you do, make sure you know where every bolt and washer belongs. Also, be careful when you take out the jets. Even after you unscrew all of them, there are three check ***** and weights still inside and you need to make sure you know where each one goes. I kept the jets sorted with an ice cube trey. They also have numbers on them if you look carefully. The blind plugs on the side of each bowl are held in place by clips and they break very easily. Be very careful when you remove them.

There are also a lot of connections to the carb also. Make sure you know what hooks up where BEFORE you remove the carb. Make a scetch/take photos if neccasary. These days, a decent digitial camera should be one of your most useful tools. There are also vacuum hoses running all over the outside of the carb. You should make a scetch of how thier routed as well.

Oh, there's a plastic spacer under the carb with a gasket on the top and bottom. Don't replace them unless you need to, they're very hard to remove.

 

You're not supposed to remove the gaskets on the phenolic spacer, nor use the gaskets that look like they fit on the spacer.

 

You darn sure don't want to use the gaskets on the spacer that do not have all the small holes in them. Those tiny holes are for supplying vacuum to the fittings on the spacer. Plug them up, and you will not have any vacuum getting to the nipples.

 

Really? My orginal gaskets didn't have holes either. I only replaced the top one but it looked exactly identical.