Help me identify this on a Ford 460 carbureted RV

[Alain2]

Helping a friend, RV late 70s, Ford 460 engine. This thing has is vacuum activated, ajustable and connected to the carburetor with a metal chain (like a toilet chain), when you open the throttle it pulls against the vacuum pull. It has electric wires to, but can follow to where it goes.

Can someone tell me what is the purpose of this device?

 

[wag123]

Cruise control

 

[PontiacHO]

Cruise control

Yes. I have also seen these used by ambulance upfitters for a high idle servo. Keeping the engine RPMs up to ensure the alternator(s) are charging at their maximum rate because of the demands of emergency lights, interior lights, and communication equipment needed on scene/transport.

 

[Alain2]

Thank you.

 

[Alain2]

I was puzzled by it, now I understand that the chain is not properly connected to the carburetor, it cannot open the throttle, it can only pull it close. Now it all makes sense.