High Idle Issue

[CharlieB]

Hi all,
A few months ago my 76 Spider was idling very rough so over the winter I decided it would be a good time to pull the carb and give it thorough cleaning. I just got around to reinstalling the carb yesterday and the car started right up. Idled good for a few minutes, then the idle started increasing higher and higher on its own.
I unplugged the idle solenoid while it was increasing idle but that didn't help.
Everything seems to be moving freely, nothing binding or stuck.
Does anyone know what might cause the idle to increase like that?
Thanks

[Nanonevol]

Which carb? Original stock? Water choke? It could be the idle is just set too high and is revving up to it's setting. Are the butterflies nearly closed when cold and off?

[CharlieB]

Sorry, forgot to mention that I have a Weber 32adfa carb.
As for the butterflies, I'll have to check tonight.
Thanks for the response

[CharlieB]

Well I checked and yes, the butterflies are nearly closed.
Could this have anything to do with the water choke? I know the marks are supposed to be lined up, but the only marks I see on the cover are the weld seams. Mine does not have the small tick mark on the cover like I have seen on other carbs like mine.

[Nanonevol]

It could be related to the choke. Have you let it warm up?

[wubie317]

Hi all,
A few months ago my 76 Spider was idling very rough so over the winter I decided it would be a good time to pull the carb and give it thorough cleaning. I just got around to reinstalling the carb yesterday and the car started right up. Idled good for a few minutes, then the idle started increasing higher and higher on its own.
I unplugged the idle solenoid while it was increasing idle but that didn't help.
Everything seems to be moving freely, nothing binding or stuck.
Does anyone know what might cause the idle to increase like that?
Thanks

Sounds like a vacuum issue to me...air is getting in somewhere. Double check that the gaskets are seated well with the spacers correct (I made that mistake once) then make sure the hoses are on in the right places. Is it an ADFA carb? If so, I have a diagram picture at https://imgur.com/gallery/emjxX/comment/1132805343

[CharlieB]

Thanks for the replies guys. Sorry I've been away for several days and have not had a chance to get out to the garage and dig a little deeper into the problem. By this weekend I should have more info.
Wubie, thanks for the picture link, that certainly helps.

[CharlieB]

Ok, I started the car yesterday and let it run for about 15 minutes. The idle was good, around 850 rpm or so. I pressed the accelerator a few times and it came back to idle when I let go of the accelerator.
I shut it off and then started it back up. This time it idled around 1600 rpm and would not come down.
I checked for vaccum leaks and everything looks good there.
Any thoughts?

[CharlieB]

So I decided to pull the carb off and clean it up again. I noticed the water choke spring looked a little rough so I replaced it.
I reinstalled the carb and started the car.
A FLAME shot from the carb! I shut it down and let it sit for a few minutes. I started the car again and it popped through the carb and another flame appeared.
Any thoughts?
I have read that this could b a lean condition, but I'm a bit timid about starting the car again.
I've also read that the timing could be off, but I checked and it looks right.
Thanks guys

[CharlieB]

Just a quick update.
I turned the mixture screw out several turns and started the engine. Seems to be idling well but I have not been on a test drive
since its been raining here.