I replaced the carburetor but this part was on the old one and I'm not sure what it is for or what it does and if it is necessary. It was a 2bbl on a 351 out of an 83 F150.

 

Vacuum Throttle Idle Dashpot
MOTORCRAFT DASHPOT-THROTTLE CD 69 | Auto Parts Direct To You

 

What does it do and do I need it..?

 

I had a similar item on a non Ford. It keeps the carb from going back to idle too fast and avoids stalling.

 

Is there a way of testing the one I have. I don't want to waste much money on this because seriously thinking of switching to a throttle body some time in the future..

 

Ford and Motorcraft put these on Carberaters and Dual Injected Throttle bodies to help reduce stall under certain conditions. Some where Vacuum operated and some where electrical. They also helped to maintain the idle when the A/C was turned on

 

This one has a vacuum port on it, would it take the vacuum directly off the intake manifold..? I remember there being a mile of vacuum lines on this thing years ago and was told to get rid of it all because it wasn't needed..

 

If it isn't raising your idle for A/C just run it without and see if you develop a stalling issue. The one on my Toyota is on a fuel injected engine and without it in place the computer had issues over correcting when letting off the throttle fast. Kind of like a shock absorber for the throttle. May not be an issue on a carburetor. Look how many don't have one.

As far as testing it a Mity-Vac should work to see if it moves or leaks. I don't know if your would be directly ported to manifold.

 

A lot of those are anti-dieseling solenoids. The vacuum holds the plunger back and when you shut off the engine, no vacuum and the plunger goes out pushing the throttle open to prevent the engine from running on (dieseling). The ones that slowed return to idle typically have no vacuum port or electrical, just a light spring to allow slow return to idle. The electrical ones are typically used for the AC when the AC got energized so did the coil to hold the idle up so the compressor drag would not kill the engine.

You should not need it but if it holds vacuum you could use it hooked to manifold vacuum and set just below the linkage under vacuum so when the engine is shut off the plunger extends pushing the linkage.

 

Like others mentioned, some engines would stall when returning to idle. However, it is just as much an emissions part. When quickly returning to idle high intake manifold vacuum creates an extremely rich A/F mixture for a few seconds. So, slowly returning to idle minimizes that time period of a rich A/F mixture. If it were my motor, I would remove it, drive it and see if there are any issues.

 

I haven't started the motor yet as I don't have the exhaust system on yet, with your explanations I'm getting a better idea of what it is and used for. I thank you all..