1950s 59 high idle when warm?

[Cadillac Jack 82]

My 59 has a bad habit of kicking into high idle when sitting for longer than 15 min.  She goes into high idle then kicks down a second later.  Is this normal for a 59?

[The Tassie Devil(le)]

Sounds like your choke setting at the automatic choke control is incorrectly set.

This is one reason I am not fond of Automatic Chokes, as if they cool down too fast, it thinks the engine is experiencing a cold start, and requires more choke.

This is more-so in the electric chokes, but as your car has the mechanical choke, there could be something wrong with the bi-metallic spring, if it has one.

Bruce.

[V63]

The choke is probably set too "rich", on the black plastic cover you should notice markings that designate rich and lien ... loosen the 3 screws and turn the cover 2 marks more towards LIEN.

[Jay Friedman]

Sounds like your choke setting at the automatic choke control is incorrectly set.

This is one reason I am not fond of Automatic Chokes, as if they cool down too fast, it thinks the engine is experiencing a cold start, and requires more choke.

This is more-so in the electric chokes, but as your car has the mechanical choke, there could be something wrong with the bi-metallic spring, if it has one.

Bruce.

My opinion of automatic chokes is the same as Bruce's and for similar reasons.  Using a kit bought in an auto parts store I converted my '49's to a manual choke with a pull cable going to a knob under the dash. I live in Georgia, which has a mild climate, so most of the year the carb doesn't need more than a few seconds of choke after a cold start.   

[Lexi]

Concur with the other posts. I have experienced a case where it was tough to get a fine adjustment especially when car still warm and only shut off for a short period. In that case a carb rebuilder had replaced the choke spring and I wonder if that spring's tension was greater-thus more difficult to obtain a correct, fine tuned adjustment. Perhaps something to consider if your choke cover plate adjustment is unsuccessful and you have had work done on your carb at a time which just preceded your idle issues. Anyone else experience this? Clay/Lexi

[Lexi]

Further to my above post; like Jay I once installed a manual choke on my '56 CDV back in the '70s and was quite satisfied with the way the car ran. Far superior to an automatic choke for the reasons Jay and Bruce gave. Just did not like the non-originality, but it ran the carb perfectly. Just have to remember to disengage it when it has done it's job. Clay/Lexi

[60eldo]

 Is your choke tube ok. I had similar problem,found that my choke tube was rotted and could give enough heat. Take off round black coil see if its clean, if all soiled ,tube is bad.

[Lexi]

Not sure if your question was directed at my 2nd last post in this thread or the OP, but my choke tube was 100% OK. Clay/Lexi

[JayRudig390]

Do you have a Rochester or Carter? Ps on this forum there are givers and takers. You seek answers but when I asked for info you ghosted me.

[Lexi]

Do you have a Rochester or Carter? Ps on this forum there are givers and takers. You seek answers but when I asked for info you ghosted me.

Are you directing your question at myself or another member? I have not received enquiries from you or anyone else so far, in association with this thread or via PM or other means of communication. Clarity is required. Clay/Lexi

[Chopper1942]

Usually when the choke spring goes bad, it becomes weaker and does not close like it should.

Give this a try but do this with a cold engine. Take the cover off the choke housing and check for debris, rust, soot. If it is clean, reinstall the choke cover leaving the screws loose enough so you can rotate the housing cover. Open the throttle a little and with the choke blade wide open, rotate the choke housing until the choke blade just closes. This should be good for the AZ temps. If it is lean and want to die when cold, tighten the choke housing 1 notch.

[Cadillac Jack 82]

I've been away for the holidays.  I have the Rochester carb.  Again its usually when she sits for about 15 min or so.  She'll kick into high idle for about a minute then I can kick it down with the accelerator pedal and shes fine.  Outside of that she runs great.

[Chopper1942]

Try this. After driving the car, let it sit long enough to cause your concern. Do what you normally do when you start the car, but don't crank and start the engine. Open the hood and remove the air cleaner. Is the choke blade closed? On the right side of the carb, look at the fast idle cam. Is the fast idle screw on an step of the fast idle cam? If yes to either, the choke adjustment is not set correctly or the spring is bad.

If the choke is not closed or on a fast idle cam step, push on the throttle lever and see if you can close the throttle. If so, either the primary throttle plate shaft is sticking/binding, linkage is binding, or the return spring is not strong enough.

If the throttle shaft is sticking, spray the inside and outside pivot points of the shaft with carb cleaner. Lube the pivot points of the throttle linkage and trans TV rod/cable attachments. If I remember correctly, your trans should have a rod and linkage from the carb to the trans. Make sure this all moves freely.

[Cadillac Jack 82]

Thank you Chopper I'll try that this weekend.