Hey everyone, I have a 1985 Mazda Rx7 street ported with the rats nest delete and have a Nikki carburetor with full emissions still attached. I’m having a problem every time I hit the gas. My idle keeps getting stuck at 2,000 to 3,000 and won’t come back down unless I pull the choke out slightly and push it back in and the idle will drop back down almost dying. Also, the idle adjustment screw Doesn’t seem to change the idle as it’s running. I wanna say it’s something with the throttle linkage getting stuck and the choke is helping it push it back in and close it. I’m not sure. Maybe it’s a vacuum leak somewhere if anyone can help me With some tips or advice that will be appreciated.

 

Here’s a video of it doing it. Also the video does get cut short. It does end up going back down to about 1000 RPM sometimes lower wanting to die 1100 is about where it’s pretty good. I’m guessing since it’s a street port.

 

Check the teeter-tooter. What mods have been done to the carb aside from the rats next?

 

well, I bought the engine was straight ported also came compared with the carburetor and intake. The engine was ported by Rob from pineapple racing, and said that the carburetor was tuned by Rob an engine was ported by Rob so I’m not completely sure the ins and outs of what’s happened to this carburetor all I know is it starts the car better than the old carburetor does. And it did run really good for a bit i’m guessing something just got stuck

 

What have you checked? Kind of hard to troubleshoot with limited info and not being able to put hands on it. Can you check the teeter-tooter? Also check the throttle cable to make sure it's not binding.

 

Sounds like the throttle is not returning or binding. Check the springs and things to make sure it all moves smoothly.

 

I took some photos of the linkages and could my problem come from the throttle opener not having any hose there also what does the little diaphragm do underneath the idle adjustment screw do? Whenever I plug it the car idles way higher

 

I wonder if that hot start cable holder arm is getting stuck in pic 5. I also see the end of a spring not connected in that same pic near that hot start cable holder.

 

That’s what I was thinking there for a bit as well. I tried getting it off of that. I got it off there turned it on hit the gas few times it still got stuck look back and it’s back on there. I don’t have my hot start assist anymore, so maybe I could figure out how to get it off that piece.

 

I think your going to need to friend and one can operate the peddle and the other inspect the linkage to see where it is hanging.

 

I got that hot start assist arm out-of-the-way plugged some plugs and sprayed the linkages with some carb cleaner and WD-40 and let it sit and it seemed to fix the issue

 

Nice.