Hey guys,
Recently picked up an 83 rx7 with the original Nikki and running into some problems I haven't faced before. At first it was flooding but a few whacks with a screwdriver fixed that. One float was too high, adjusted down to just barely above half on both. Accelerator pump wasn't working, took it off and the check ball was stuck, cleaned and works great now. Took off the jets and air bleeds, cleaned so they all flow properly and reassembled.
It runs great if I pour some fuel down it but it refuses to pull its own fuel even though the bowls are full, wondering if they're are certain passages that might be clogged or something else I'm missing? First time working on a Nikki or an rx7 in general.
Thanks!

 

Sounds like you did a partial cleaning and fixed some issues. Its not clear if you used a rebuild kit or not. I would suggest completely removing the carb and separating the 3 pieces (base plate/throttlebody/carb) and cleaning them with a good solvent. Blow out all the passages and replace the gaskets all around. Don't mess with trying to do gaskets on the plastic base plate, just make sure its clean and all the passages are cleared out. Also don't use the new needles or seats from any kit you get, clean the old ones and reuse.

 

Will it run on the main circuits?

The Nikki that came on my '81 looks absolutely beautiful, no corrosion, all hardware still brightly plated, etc. But the idle circuit won't work. As far as I can tell all of the passages are clear, although this doesn't tell me if there is an air leak or not. It would run at high enough RPM to pull from the mains but it wouldn't idle.

After a lot of screwing around, checking this and that, head scratching, etc, I gave up and bought a used carb on eBay because I just wanted to drive the thing. It's ugly and leaks and I had to rejet it because it was running lean on the primaries at highway speed but it runs, at least.

 

I did not use a rebuild kit, I'm gonna order one but it'll take a while to get here and I want to get it running enough to go around the block to test other things on the car. Thanks for the info, I'll follow it when I get the kit. So the baseplate will seal without a gasket?
Also any recommendations for kits?

 

It will not run on the main circuit. The only time it'll pop is with the accelerator pump or with brake clean or fuel down the throat. Bowls are full, fuel pressure at 4psi, return line hooked up, bowl vent open. Spraying carb clean in the jet when it's installed shoots fuel out the venturi, same with spraying it into the bowl vent.

Other things to note, it appears someone has filled the upper accelerator pump port with rtv? There's also a spot in the v section where it looks like it might be missing an air bleed?


Got a lot of cleaning to do and definitely needs a rebuild but I want to be able to drive it short distances to be able to move it and see what suspension components need replaced.

 

I usually just get the Hygrade kit on rockauto and use what I need from that. https://www.rockauto.com/en/moreinfo...t=5964&jsn=549

 

I just finished rebuilding an 84 manual carb with some 85 manual carb parts. This was my first and only carb rebuild and I now have some parts left over.
The first attached image is the main body with all the internal pieces in place for reference.

I cannot tell from your image if your carb is for manual transmission or automatic. The manual ones have a richer solenoid below the triangle on the right side. The automatic ones have a blank hole.

If you have a manual carb the second attached image shows my 84 parts you are missing.
The numbers 93, 94, and 73, 74, 75 reference the parts listing in the Mazda Carburetor Manual parts listing, an extremely helpful publication. (Available for download by following the links in the Download your FSM post in the stickies at the top of the forum.)

For both the 84 and 85 carbs I had, part #93 has two parts: the cylinder pictured which goes in first and then the plug. Part #94, the idle richer air bleed and jet, goes next to #93 and sticks up.
Parts 73, 74, 75 go in the hole on the right-rear which was filled in on your carb. The check ball goes in first, then the small weight, then the larger check valve seat.

Let me know if you need the parts.

 

Mine does have a manual trans but I'm not sure of the origin of this carb. Supposedly it's an 83 and the proper carb for the car but I don't think it was the original that came with the car. The filled port does in fact have all it's pieces in it and they do move freely, the accelerator pump works great now so I think it being filled is fine just no clue why it is. Not sure of the differences between the 83 and 84 carbs or what the deal is with this one but my kit just arrived and I'll try and throw it together tomorrow and see if I need anything.

 

I'm not sure if you need any of the parts I pictured before.
You have the check valve.
The idle richer and air bleed is not listed for 1983 models in the specifications.



When serching on ebay for parts I wanted an 84/85 manual transmission carb.
Auto transmission carbs do not have the richer solenoid on the right side of the main body.
83 - 85 have the newer version of the air vent solenoid on the left side of the air horn.
Only 84-85 have the addition of a #2 Main Air Bleed in one of the two vacuum lines on top of the High Altitude Compensator connection.





Sub story. I found a fully configured carb ad on ebay. It had all the right pieces to be an 84-85 manual transmission carb. I check with the seller and was told I would receive a carb exactly as pictured. When I opened the box it was an 83 manual transmission carb, which I returned.

 

Damn that sounds annoying, online shopping is always a gamble. I think either way it should still run if it was configured that way for any model from the factory.

Went ahead a rebuilt it today, everything went good but still not able to pull fuel from the bowls. At this point I was thinking I must have a damn big vacuum leak so I went ahead and smoke tested it and the intake manifold was dumping it out. Turns out the two block off plates a previous owner installed never had a gasket put on. Made gaskets, reassembled, same thing. Decided to take off the manifold and see if something was up with it and low and behold the lower left corner was broken clean off.

So I guess it wasn't a carb problem after all I just had a massive hole in my intake new one should be here later this week and hopefully it'll drive.