Question - what causes engine run on after it has been shut off?

I recently changed my fuel pump and readjusted the carb. Timing is set to factory specs 12 deg adv. Car runs GREAT, but when I go to turn it off it wants to chug on for a couple seconds. Is it a carb or timing adj. ( or both)?

Any help is appreciated.

If memory serves me correctly this can be corrected with an anti-deseiling solenoid. When the ignition goes off it releases a plunger that pushes the throttle blades all the way close cutting off all air so it kills an engine.

Does anybody know if this is correct or just the redneck way of doing this

too much fuel

did you adjust your idle mixture screws ??

I'll go with cthulhu,
Idle might be a bit high also, and might back to timing to 10 and try that.

Yes, I did readjust my idle mixture screws. Seems to run better a little rich. I guess I can start by leaning it out little by little. The idle is set to factory specs - 900 park, 650 drive (Automatic / 350)

Thanks!

well if all you did was change carb id say leave timing out of it..

and if idle is right.. then mix screws..

did you adjust the screws with a vacuum gauge.. (non ported carb or intake vacuum)

Ben -

Your suggestions are appreciated.

Yes, I did use a vacuum gauge. Max vacuum I could obtain was 16 hg. I do not have vacuum advance so that is not a factor. I first warmed up the engine and set the idle in park (900 rpm). I then turned off the engine and set the idle mix screws at 1-1/2 turn out from seated. Next, started the engine and fiddled with idle mix screws together to obtain max vacuum and rpm. Once that was achieved, I adjusted the idle with the car in drive (600 rpm).

How does that sound?

From your member name, I assume you have a 73, which means you should have the anti-dieseling solenoid. When you set the idle speed, the solenoid should be holding the carb linkage open, and you adjust the speed by screwing the solenoid rod in or out. The little screw on the side of the carb is for the fast idle adjustment, and shouldn't be contacting the linkage when the choke is off. The solenoid gets power from the radio/kickdown circuit. Joe

Hey Joe.

The carb is aftermarket (edelbrock). No solenoid present. Maybe that is a problem.

Bret

Hinz-73 said: Ben - Your suggestions are appreciated. Yes, I did use a vacuum gauge. Max vacuum I could obtain was 16 hg. I do not have vacuum advance so that is not a factor. I first warmed up the engine and set the idle in park (900 rpm). I then turned off the engine and set the idle mix screws at 1-1/2 turn out from seated. Next, started the engine and fiddled with idle mix screws together to obtain max vacuum and rpm. Once that was achieved, I adjusted the idle with the car in drive (600 rpm). How does that sound?

sounds right..