Carburetor question

[mgl00]

Help please with identifying this part and what is it supposed to do, and does the set screw pictured play a part in the function of this part. It is identified in the exploded view as "dash pot", I have no clue, it does not seem to do anything if I push the rod in/out against the spring. This is a 1 barrel carb on my 1980 f-150 300 cu in Inline 6. This carb appears to have an electric choke.

thanks for the help.

[81-F150-Explorer]

That is a anti stall Dashpot. My 300/6 also has one that is slightly different on it's YFA.

The purpose of it is to hold the throttle open slightly for a second or so, thus preventing the throttle from closing abruptly, to prevent stalling.

Without it your engine could stall coming up to a stop light or stop sign, with your foot on the clutch, and foot on the brake. If the truck is manual.

The set screw adjusts how long the Dashpot holds the throttle open for, and how high it holds it.

The dashpot can also be adjusted where it attaches to it's carb bracket.

Some Dashpots are heat sensitive and may not operate fully when the engine is cold.

Hope this helps.

P.S.

To adjust the dashpot have the engine warm and at correct idle speed. Rev the engine and see if the dashpot holds the idle slightly higher for a second or so. If not reduce the amount of space between the screw and the dashpot until the dashpot holds the idle slightly higher for a second after reving.

Hope this helps.

 

[mgl00]

Thank you, fantastic explanation... do I need to adjust that set screw to touch the rod, I don't see how it would keep the idle up if it is not touching the set screw.

[81-F150-Explorer]

Thank you, fantastic explanation... do I need to adjust that set screw to touch the rod, I don't see how it would keep the idle up if it is not touching the set screw.

Yes it does need to be touching to work.

However if the engine is cold, the Dashpot may not touch and still be adjusted properly. Because it is supposed to work with the engine at operating temp.

PS

This is why I adjust mine with the engine running at operating temp.

[mgl00]

Yes it does need to be touching to work.

However if the engine is cold, the Dashpot may not touch and still be adjusted properly. Because it is supposed to work with the engine at operating temp.

PS

This is why I adjust mine with the engine running at operating temp.

Thanks again !!!! It all makes sense now ! Really appreciate the help, just starting to get this truck on a long restoration project...first thing get it up and running and safe to drive...