The automatic choke on the '52 DeSoto Hemi in my roadster wasn't connected when I got the car it came out of. There's a port on the choke, there's a port in the intake manifolds heat riser that I THINK a tube from the choke is supposed to set in, but, I did that a couple days ago and it ran TERRIBLE. Choke didn't work, the engine stuttered and backfired, so I took the heat tube back out, and just left it open like it was. Whistled because of the vacuum leak, so today I just put a pipe plug in the choke port. I plugged the intake manifold port to stop the exhaust from chuffing out of that. The choke works. It runs great, as the video shows, so I think I'm going to leave well enough alone. https://www.facebook.com/video.php?v=1791200581272343
You obviously figured out that it runs better without the vacuum leak. The next question now is, how does it start? If the cold engine fires off without having to pump the gas pedal to extremes, it might be good enough as is. But if it needs the choke function for starting, a manual choke is a simple enough answer. You don't have to mess up that nice-looking dash. You can tuck a push/pull knob under the dash to keep it simple and reversible.
I’m a bit confused, is the port on the carb some how related to the choke? I/e is it supposed to slowly open the choke as the the engine heats up? I ask because you said the choke works, is it the automatic function that doesn’t? The reason I’m confused I guess is because only know of two types of chokes I’ve had, manual, and (what I thought was automatic, maybe not?) where you hit he pedal to set it on the fast idle and close the choke. When the engine heats up you give the pedal a tap and the choke opens and the lever goes off the fast idle. Anyways, if you’re happy, so am I
When you put the tube on it the exhaust leak you had became a constant flow egr system there should not be an exhaust leak there. There probably was a stainless tube running thru the manifold at some point in time that p***ed all the way thru the manifold that kept it from leaking. The choke tube pressed into that tube so it only drew hot air.
I'd bet a coffee if you took the mechanism apart there's a control disc in there that allows a slight vac leak when choked, as the bimetal spring does its gig the disc closes off the vac leak, and that disc is probably burned away just enuff to leak all the time. But I'm with you if it's running right, let it be.
Yes, I think that's what's happened. Without the plug in the choke (a regular flare fitting), it "whistled" all the time. But, it pulled the choke ****erfly shut cold, and it opened up when warm. It started at the touch of the key, warm or cold. Seems to operate the same way with a plug in the choke fitting, instant start, warms up and the choke opens up, comes of down the high idle as it should, and it still runs great. I'm inclined to leave well enough alone, although I think I'll solder the Nicop line shut that I made, press it into the exhaust port in the manifold so it looks "right". I totally admit I don't understand all know about this, but if works, don't fix it is my motto...
I fired it today. Cold. Standing outside the car, no throttle. Didn't turn one revolution and was idling at 650, smooth and steady, just like in the video when it was warmed up at 180. It's good to go. Now, if the weather holds even a little for the next couple weeks I can MAYBE get 2,000 miles on it.
If it works, don't mess with it. You may already know this, so don't be offended if I'm not telling you anything new, but there's a coil spring in the choke housing that will coil tighter when it gets cold, and that will close the choke. With the tube installed it's supposed to draw warm air from the heat riser and that warm air will cause the spring to expand, or uncoil, opening up the choke. That's the theory anyway. But what the heck, if it works, I agree, leave well enough alone. Cheers.
The pipe to the automatic choke come from exhaust manifold. On my 53 Dodge it is a clothed pipe from right exhaust manifold to the carburator. I found a good picture on the net that shows it. The pipe goes back and around the valvecover and in to the exhaust manifold.
In other news; show of hands, who knew that the 810/812 Cord had an electric choke incorporated? Yup, sure did. 1936. History is fun...
That's exactly how I routed it, aside from the differences between the Dodge and DeSoto engines. My mistake was in no accounting the constant vacuum in the tube ****ing exhaust into the carb. Which makes me think my solution of soldering the tube closed where it drops into the heat riser, then sealing that so exhaust doesn't "chuf" around it, and I'll be good, and it'll look proper.
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