So my '74 2.0 w/dual webers just started revving 2-3K rpm's when I push my foot on the clutch. One of the carbs has been leaking, and when I first got the car in August, the mechanic said there was some sort of "bent plate" in the carb, and he couldn't get it quite tuned correctly, said the idle would be a bit high. Until yesterday, it hasn't been a problem at all. I know nothing about carburetors, so is this something that could be fixed by turning an adjustment screw? Or is it time to get the carb replaced?
TIA

Sounds like the throttle cable is wrapped around the clutch cable near the pedals (easy to do), or the clutch tube has broken the weld in the tunnel.

How would I get to that area? From inside the cab?

Lift the carpet on the driver's side. You will find a black (usually) wood pedal board. It can be removed but is tricky and you have to work it at the proper angle. You will also have to remove the rod from the back of the rubber gas pedal (pops out).

To confirm this is the issue - disconnect the linkage back at the engine and see if depressing the clutch raises the throttle.

If it is a broken clutch tube it becomes more involved - you can search for solutions here but you might can inspect the movement from the tunnel cover plates on the cabin.

Thanks, I'll check to see if this is the issue.

I disconnected the linkage at the engine, depressed the clutch--no difference. It's running about 2800 rpm's.

Got it - I thought the idle increased from normal to 2800 when the clutch was depressed.

Yep - something else is going on here...

Back the pass idle speed screw off of the stop. Measure the flow @ the front 2 venturis. No telling what the last mechanic did. Start over and go thru the pre-install setting/adjustments. It should take about 15 minutes. With the cable disconnected at the linkage, do the throttle plates close with authority on their own? possible you have a bind in the linkage.

However, with the linkage connected, and the car running, if I rotate the bar that the throttle cable is connected to, I can make the idle go back to normal. I don't know what this means, but thought I'd add it.

You should not have to force the linkage. Do the pass side ISAS and see if you can then bring the idle down with the drivers side. The purpose behind this is finding out if one of the drop links is holding both of the carbs open a bit. One side off of a stop lets the carbs follow suit. If you don't have a/the correct device to measure the side to side flow you're working in the dark. Post pictures of the carbs and linkage you are using.

Sounds like the linkage assembly is sticking or the spring return is broken or disconnected.

With throttle cable disconnected you said earlier the car still revs at 2800??? Sounds like a jam somewhere. At best a tight linkage bearing or defective spring. At worst a loose butterfly in a Carb that's catching.

I'd take off the air filter and shine a flashlight down the carbs to check the butterflies and especially the two tiny screws that hold them on the shafts are all tight.

Doubt its a drop link at such a high RPM and him turning it by hand wouldn't reduce back to idle.

"Sounds like the linkage assembly is sticking or...". That's the point. Slop in old heim joints, worn pivot balls, centering springs that don't. Components that give and the system flexes. No telling how much pressure it takes to bring the idle down by hand. There's a natural side load that occurs due to the the offset of the carbs. Much of ANY shift and 'fixes' go out the window. My suggestions take about 1/2 hour combined and rule out a host of potential problems. Even over tightened nuts on the throttle stop arms screw things up.

OK, I'm a total noob when it comes to carbs, but surely I can learn
I looked up the Redline website, and found a section ford IDF Carburetors/ Low Speed Circuit Tuning. Is that the ISAS you talk about? What sort of device do you need to measure the side to side flow?

This is from the service ticket when I first picked it up:

"Tech attempted to balance carbs. Right carb on cylinder #3 had too much flow (twisted throttle plate), can't balance properly. Test drove, ran too rich. Removed #170 jets and installed #130 jets. Test drove, ran better. Removed idle jets and replaced with #60. The idle jets were worn to between #63 and #66. To adjust and set better, would need to tune with custom jet sizes."

This is a '74 2.0 that is supposedly rebuilt to a 2.2 with 44 IDF carbs. I've added some
pics
First time I've added pics, so sorry they are sideways. In the first one, you can see the fuel leakage at the bottom of the carb. The second shop I took it to said that carb would need to be replaced because of the leak.

Is the fuel on the bottom of the carb coming from the carb/intake junction or dribbling down from the carb top plate? I can't tell from the photo. Is that the Venturi with the bent throttle plate? I think you are going to have to investigate this plate issue further

I can't find any indication that the fuel is dribbling down from above, it looks like it's coming from the carb/intake junction. I've tightened those nuts as far as I feel safe doing.

trying to get pic in the correct orientation

you tube is your friend. your linkage maybe set up incorrectly. like other suggested disconnect the linkage once the car I started, then buy a syncrometer to measure airflow to balance.

bent butterflies is not that common. incorrectly setup carb linkage very common problem.

https://www.youtube.com/watch?v=92ZAh3l2Nh4

I love my carbs been working on them for 25 years.

buy this book:

https://www.cbperformance.com/ProductDetail...roductCode=0103

procedure
http://www.aircooled.net/synchronize-dual-...arburetors-103/


tool
http://vwparts.aircooled.net/Snail-Type-Sy...SK-p/ste-sk.htm