Throttle stuck wide open with closed butterflies on the carb
 

I run the stock nikki carb and when i start the car it goes straight to redline the throttle cable is fine the butterflies are closed on the carb i dont know what to do or what causes it to do that please help

welcome to the board. :)

is the car new to you? do you know when was the last time it behaved normal?

you mentioned the throttle cable is fine. have you checked the choke cable?

I have had it for 3 years i pulled the engine out for the second time in my ownership to fix the o ring from the front plate because i had low oil pressure i put everything back together and when i turn it on it goes instantly to red line all the cables are fine i am really confused

did you have any reason to remove or mess with the return spring or any of the springs on the carbie?

No all the linkages outside the carb are fine i didn't mess with the carb at all but the only thing I did is that i removed the 4 bolts from underneath and put it upside down on the part between the windscreen and the hood only that i think might have messed something up, the fact that i let it rest upside down

what about vacuum? i'm not sure a vacuum hose could make it rev so high, but have you double-checked that the carb and/or gasket are seated correctly?

Yes i did that, also i tried playing with the mixture screws i closed the idle screw and the fuel screw all the way and in theory it shouldn't turn on but doesn't change anything still goes for the red line i unscrewed as much as i could to see if there was a difference still nothing

okay. if the idle screw are not making any difference one way or another, then that (to me) sounds like a leak. there should be a nipple coming out the intake manifold (the rear secondary runner), near the tranny. it's sort of hard to see. check and see if the hose is not connected or broken.

Sorry for taking that long to reply I will check it tomorrow and i will inform you, thank you

Also because I now think i messed up the carb tune do you happen to know a baseline for the idle and fuel screws?

download the FSM: Foxed.ca

there is a procedure in there to set them.

also, this link may help: https://www.rx7club.com/1st-generati...e-carb-310927/

I rebuild the carb and still the same.. could it be the timing i mean the problem happened after i pulled the engine out and put it back in while i didn't do anything on the carb could i have advanced the timing so much ???

did you check that port/nipple on the back of the manifold?

timing? for what you're describing, the simple answer is no. besides, when the RPM goes up because of timing, the adjustment screws still have an effect.

here's a random thought, are you sure the throttle shaft is not twisted or bent in any way? i saw that happen once with an Rx-3 carb. bad idle, not exactly what you're experiencing, but i'm running out of ideas.

Is the tittrer-totter still attached on the back side of the carb linkage?

the throttle blades are closed and it goes to redline i checked the linkages many times sadly they are not the issue, what is the tittrer-totter?

if you find where the main throttle spring (the big one with the rubber shield) attaches at it's upper end, that linkage is the teeter-totter.

you will see it in post #81 of this thread: https://www.rx7club.com/1st-generati...-964025/page2/

Mine doesnt have a teeter-totter maybe its because its for the EU market


https://cimg4.ibsrv.net/gimg/www.rx7...a16735f165.jpg

Can you post more pics of the carb? I have a hunch someone removed a bunch of stuff off this carb.

as i said it happened after i had pulled the engine out of the car i didnt touch the carb i didnt even take out the fuel lines and rested it in front of the windscreen i havent pulled anything from the carb before this issue started.

Troubleshooting at this level is only good with a known configuration, i.e. all factory parts without modifications. Based on what I see, your setup is not factory. It could be a EU factory setup, but I don't know what that is. This is where the pics help.

What irons did you use (I'm assuming you rebuilt the engine when you removed it).... SA plates have large holes where some FB plated do not; large enough to make a giant vacuum leak IDK, its worth a look.

i didnt rebuild the engine i took it out because of low oil presure i removed the front cover to change the o ring this is the second time i took the engine out for the same reason

You might try making a blank (wood, metal, whatever) to bolt on top of the carb in place of the air cleaner. If it still starts up and runs, then it seems to me you have to have a vacuum leak. With the inlet of the carb totally blocked no air can get in there, so it seems like it would have to be a leak. Of course, you will still have a vacuum on the carb so fuel will still be getting sucked in through the idle and probably main circuits. Seems worth a try.

Carl