Does the AAR on a 73 2.0 ever close completely ?
Does it operate on 12V only or does it rely on engine ambient temp to operate as well ?
I have a high idle after adjusting timing ( with known factory timing marks ) and checking all areas for vacuum leaks.
If I cap the AAR hose the idle is normal and there is adjustment left on the idle screw.
The points plate moves freely with vacuum in both directions.
TIA

AAR is open when no voltage present, air flows freely. when 12 volts applied, within a few minutes, but under ten minutes, it closes off completely and no air flows.

It's a coiled up spring.

Blast a can of pb blaster into the inlet, shake it, let it dump out...keep doing it untill all the rust falls out, and dirt.

You can run two wires to it for testing.
Power lead is obvious, body needs to be grounded.

No air should blow through when it's closed, if it does, let it cool down and clean it again....needs to be one to clean, so cold..

Remove it and as Rich said PB it or WD40 it. Placing it in the freezer for an hour then apply 12V. Repeat until it fully opens & closes. It will operate w/o power but takes longer to seal off when engine heat is it's only source.

That is a good test. After initial start there should be vacuum at the AAR, you should be able to watch this go away within 5 minutes. The manual has an actual spec time. If the car has been running for a half hour you should feel NO vacuum. Wire attached and 12 v with the ignition on?

I have two in the freezer now. May find others if I look hard.
Earlier I had both attached to 12V for a half hour and both were as open as a whistle. They both got pretty warm ( 140 + - ) but I could not detect a restriction going on.
Sooooo, clean and tap and clean and blow through and clean again and they come back ? My fingers are crossed.

If that fails (hopefully it won't) after several tries, you can pry the lip of the can open from around the top part. The top, valve, and spring all slide out. You may be able to use a slot-head screwdriver on the bottom of the valve to turn it, freeing it up.

--DD

OK, pried it open pretty cleanly.
All looks pretty simple.
Removed the bi-metallic coil
That shaft is #@%#&($ waaay stuck !
Just to be sure..... the pie shape piece is the fixed part right ?
Break out the torch ?

Never mind.
It freed up.
I didn't want to be too aggressive and ruin it.
Thanks all..... now to see how well it works !

I found this awhile back. Maybe it might help someone.

http://members.rennlist.com/pbanders/idle.htm

The provided link included a complete "how to" for AAR repairs.
Have now disassembled both of mine and freed both up.
I'll have time to test them tomorrow.
Thank you for the great help.

The cylinder with a slit in it is the "rotary valve".

--DD

Wanna sell me one. I have a 74 2.0 I need one


Niece 914 luva