So. I learned this morning that the diaphragm assembly sitting on top of the #3 runner of the intake on my 1966 Olds Starfire is a dashpot. What I am having trouble with is, what exactly does it do? I don't see how it does anything. It's not attached to anything.

 

If it was used in '66 the way it was in later years, it keeps the throttle from slamming shut too quickly. When you take your foot off the gas, the tab on the throttle lever on the carb hits the plunger of the dashpot and stops short of closing all the way. Then, as the throttle spring continues to apply pressure, the plunger slowly presses in, allowing the throttle blades to finally close all the way (idle).

Usage varied, but quite often a dashpot was used on automatic cars with A/C (due to the extra load of the compressor wanting to kill the engine) and on all manual trans cars (presumably because they don't have the back-drive of the torque converter helping to keep the engine revving).

 

^^^This.

The dashpot is a "shock absorber" for the throttle plates.

 

As I understand it, without a dashpot, cars of that era could stall if you lifted your foot off the gas pedal abruptly at high speed, such as you might do as you exit a freeway, as the throttle would close too quickly.

Remember what a "dashpot" actually is. It's basically a shock absorber.

http://www.wikiwand.com/en/Dashpot

 

Thank you guys so much. I think i will need to be looking to replace mine since when I was taking stuff apart I dropped something on it I think and the plastic sleeve, I guess, that the "button" slides in, broke. Everything appears to work still, ie the cushioning effect the baffle has, but it IS cracked beyond what is visible on the outside. Is this one going to be a 66 Starfire specific item (God help me) or will an aftermarket one I found work?