You never know when I'ts a Good Day

[Bullitt-]

Till you found that long lost part. 

  Been a bit depressed the last couple of days, seems that everything I've tried to accomlish this weekend has gone nowhere.. Looking through my many stashes of parts trying to find a piece or two of hardware that's gone missing I pull out an item I don't believe I've laid eyes on in almost 30 years..
    If you've never seen one this is the fast idle solenoid for a '73 340 Thermoquad.

[Glennster]

What does that sucker do?

[Bullitt-]

It mounts on the right front & is energized when the alternator is, actually plugs onto the alternator & has a receptacle for the alt. wire in its plug.  Seems that it opens the bowl vent tube that goes to the vapor caniste CORRECTION
Idle Stop Solenoid (ISS):
    71-76. Useed to set the idle higher than the basic curb idle screw for emissions reduction and to allow further closure of the throttle blades at engine shutdown to prevent 'deiseling' or 'run-on'. Mounts on a bracket retained by base mounting bolt and screw on the right side for 72-76. 71 mounted to the left side of the intake under the carb linkage. http://www.carburetor.ca/Tech/Carter/tqguide-Vaanth.html
  ...here's a pic of hoods' with it in place.

[BIGSHCLUNK]

Its always nice when this just fakk into place! 

[miketyler]

I thought they also had a similar idle-up solenoid for AC cars. Would kick up the idle when the AC was running so it maintained consistent idle speed.

[Bullitt-]

I thought they also had a similar idle-up solenoid for AC cars. Would kick up the idle when the AC was running so it maintained consistent idle speed.

It could very well have been used for that as well, I always thought it was for raising the idle when the alternator was energized(my car has no A/C)

This clarifies it.... I misunderstood the first time

Idle Stop Solenoid (ISS):
    71-76. Useed to set the idle higher than the basic curb idle screw for emissions reduction and to allow further closure of the throttle blades at engine shutdown to prevent 'deiseling' or 'run-on'. Mounts on a bracket retained by base mounting bolt and screw on the right side for 72-76. 71 mounted to the left side of the intake under the carb linkage. http://www.carburetor.ca/Tech/Carter/tqguide-Vaanth.html