I'm borrowing a friends RX to scoot around in until I get mine back up and running...

Anyways, it's 100% stock 85 GS and the idle is running high... in the 1800 - 2000 ish' area.

I already tried adjusting the idle speed and mixture screws but that did nothing.

I checked the throttle cable thinking mabybe it was too tight but it's actually really good... slightly just ever so loose.

I then did some searching here on the forums which lead me to pick up a can of gumout... (it was what the parts store guy recommended). I sprayed it around the engine looking for a change in idle, but nothing...?

Any ideas..?

 

Does sound like it could be a vacuum leak.

Check this hose.
https://www.rx7club.com/1st-generation-specific-1979-1985-18/hose-question-750125/

 

As 74RX4 has stated there is a vacuum leak.

Why do you guys automatically start trying to adjust the idle and mixture?
By doing that you now have screwed it all up and will have to readjust after you find the cause of the high idle plus if your friend has to pass emission testing the smog shop will have to readjust the mixture. :-(

 

also, as a good measure check the throttle opener for proper function as well as making sure the choke cable is not sticking

 

Im leaning on throttle cable .... had the same problem on mines .... loosened it up and idle went down, doesn't hurt to try . good luck

 

+1 on vacuum leak, check that hose is VERY common, and if the vacuum leak is big enough you'll have a hard time finding it, but the 2nd most common would be the intake manifold gasket being rotted

 

74RX4, I did check that hose out after finding your thread in the search... I just forgot to mention it. That hose is fine.

Doctor, I just went through the whole idle / mixture screw adjustment on my YAW for better gas milage reasons. I don't think it's going to be a problem getting them back where they're supposed to be once this problem gets sorted out.

Blkdeath, Don't u mean small enough..?

Just thinking out loud, would a small vacuum leak cause the idle to go so high (1800 - 2000ish)...???

How big / high can a vacuum leak send the idle before the car won't run..???

She's running smooth. The exhaust is soooo stock & quiet comapred to mine I easily forget about the high idle.

I'm going to take a look at the throttle, choke, cruise cables again... make sure all is well one more time.

 

That's a bit high for a vacuum leak. I recently did a carb rebuild, idle was 1500 and everything was right, I thought. Turned out the cruise control cable was adjusted to tight. Idled fine at 500 after that was backed off.

 

it could go either way i've had a HUGE vacuum leak where my intake gasket ripped from underneath the manifold (PO didn't know how to fix it)it's hard to reach with any kind of spray, and then you do you gotta spray the **** out of it or else you wouldn't notice a diff. it's so big (i had to make my car idle at about 2500rpm or else it would run like ****) then i've had a really small one that while checking around i could sometimes find the general area, and sometimes i'd spray over again and it wasn't there anymore (that time i only had to raise the rpm up to 1200) btw the only thing that worked for me was carb cleaner or the Fuel starting spray.

 

Alright so there is no cruise control. There are three cables going to the carb... throttle cable, choke cable from inside the cabin, and a choke from the driver side fenderwall. I completly disconnected all three while the car was running and it still holds at 1800 - 2000. That would rule cable issue out.

Doctor, unless I didn't notice it before which I don't think is the case, you were right... messing with the idle and mixture screw wasn't good. With the idle wrong... I can't get it back to the right spot. I should of counted how many turns I went eitherway before messing with them. I left the car unattended last warm-up with the choke out & when I come back I smelt burning... Turns out the cat was glowing.

I'm going to try spraying around with carb cleaner again... if that don't work I'll give the starting fluid a shot.

 

The idle speed screw does nothing? I can understand the mixture doing nothing with high idle, but the idle speed screw should make it rev higher if its turned in. The end of the screw pushes on the linkage. Maybe you bent or incorrectly connected the fast idle rod. Unscrew the idle speed screw so its not touching the linkage and push the linkage in the idle direction by hand. If you can make the RPMs lower, even a little, as you put pressure on it you probably have something bent in the linkage.

More carb pictures....
http://intertron.com/ron/carb.html

 

you try adjusting the screw right under the throttle linkage yet? there is a phillips idle adjustment screw under the throttle linkage and to the left. Hard to see but it's there.
not sure what you mean by the idle speed and mixture screw. not the ones in the middle of the carb. I'm suggesting the one by the throttle linkage. good luck

 

The idle and mixture screws definatly did raise the idle if turned too much... I forget which one did what exactly, but by doing nothing I meant as far as lowering the idle.

74RX4... the hose you mentioned earlier I decided to actually take it off and give it a better look and it DOES have a crack just like your link explained so I changed it out.

Then I went back to the idle and mixture screws, and got the idle to finally come down... Got it to 1100ish and was happy enough for the time being, so I took it for a spin around the block... and then bammmm back to 2000 again.

Come back inside, check this thread...

Go back outside and poke around the area 74RX4 most recently posted a picture of and sure enough... There's a sticky point on the linkage that seems to not want to return back to it's position where it allows the idle to falls below 2000...

A fresh cup of coffee and I'm back going back out to see if I can figure out the reason.

THANKS a bunch for all the help...!

 

hell yeah, atleast you got some of it figured out haha, spray WD-40 or spray on grease around the linkages and all that may be an easy fix, if nothing else, it wouldn't hurt to lube them up a bit

 

Hell yea is right... A little bit of the white lube spray and working the linkage back and forth a bunch of times did the trick.

Got the idle down to a quiet and steady 800-900ish...!!!

 

the + adjusting screw by the throttle linkage; on the left of it will set your idle for you.

 

Yup, thanks... I learned that awhile back through this thread:

https://www.rx7club.com/1st-generation-specific-1979-1985-18/gas-mileage-things-i-tried-753513/

I wanted to post that link cause it has helped me on more then one occasion and help anyone searching in the future...

But to remember this already stated above:

And...

^ Definatly favorited that link...

 

I love it when a plan comes together

 

Yea man' THANKS 74 for your help.