We recently rebuilt an Edelbrock 1406 carburetor for my 340. It was the electric choke model and we removed the electric choke and wired it open. The car starts instantly and sounds great! However I can't get it to idle below 1500 rpms..I have tried both idle screws on the carb to no avail. Is there something that should have been removed on the carb? Thanks! Ted

Fast idle cam stuck in place?

Good guess although if the choke is wired open should be OK UNLESS the linkage pieces were installed wrong.

Either something is holding the throttle blades open (primary or secondary) or there's a decent sized vacuum leak. Has to be getting air from somewhere

Thanks guys! I will look at it later. I do have a pipe plug in the bark port of the carb with thread tape on it. The other two ports on the carb go to the valve covers.

Should be 3 on the front and one on the back.
The rear port should be used for power brakes or other item needing a manifold vacuum source.
The 3 front ports are for:
Red: Ported vacuum for vacuum advance if used. if not plug
Orange: PCV in one valve cover :NOTE: The other Valve cover needs an open breather or to be connected to the air filter base
Green: Manifold vacuum. Can be used for multiple things requiring manifold vacuum but it too small for PCV. If not used plug. NOTE: good source for vacuum gauge when setting mixture etc.
Some will argue to run the vacuum advance off this port but I'm not going to get into that discussion as it is almost as bad as are you a democrat or republican and why? Myself? I'm an independent 🤣🤣🤣👍

Did you plug the vacuum port to the electric choke housing after you removed it? Manual choke carbs have a brass plug installed there.

What he said.been there

I should have been clearer....I have it hooked up as you show TJP...

I will look. Thank you!

The way I was shown how to do it years ago to get the idle and mixture screws in the ballpark if you don't have a vacuum gauge handy is to gently bottom the mixture screws out one at a time and turn them back out in 1/2" turn increments looking for the fastest idle speed you can get on the tach and stop when moving them out more doesn't speed the idle up. At that point turn them back in towards the carburetor like 1/4 - 1/2 a turn at most. At that point the idle speed will be up so then you move to the idle screw on the right side linkage to lower the speed back down.

This is good info..

https://youtu.be/_AgqTUJr8aM?si=4k0HkkAsHX1zWaU4

Also these carburetors need the float drop in both directions to be set just right or they will do strange things when driving. The ones I have bought over the years I just take them apart before running them and verify that right away. Once you get them set up properly they will go many miles without having to do anything to them.

Pulling in air without fuel won't raise the idle speed. You talk of mixture screws, but you have an idle screw. When it is backed out, do the blades close completely? No hole drilled in primary blades?

I missed the part about him removing the choke I think you likely 🎯 it

There was no vacuum port there in the place where it is on a 1405.

A 1405 is a manual choke carb that may or mar not have to port drilled. If drilled it would have to be plugged or a leak would result.
The 1406 is the same carb but with an electric choke. It would have to have the port for the choke to function properly.

Which do you have?

I would put the electric choke back on it myself.

I had a manual choke model once and you had to monitor the choke cable setting as the car warmed up or it would start to run rough a few minutes into it on cold days. Car would start and idle so much smoother with the electric choke.

1406

These two pictures show where the port is





You will need to seal it

The article I got it from shows how to add an electric choke

https://www.hotrodhotline.com/md/html/electric_choke_conversion.php

That's how they work and why its called "manual"

"I had a manual choke model once and you had to monitor the choke cable setting as the car warmed up "

I am still confused on his symptoms and he hasn't answered the question on throttle blade location. The car idles at 1500 rpm.

If you have a manifold vacuum leak, or throttle shaft leak does that make the RPM go high? All the leaks folks are taking about are below the throttle blades and would be additional air that leans out the mixture. None of those leaks pull in more fuel do they?

A little but I guaranty the throttle blades are way to far open, of course the cable might be holding it open too, remove it to see.