1940 LaSalle Choke

[CraigD]

The automatic choke on the Carter carburetor on my 1940 LaSalle model 52 doesn't seem to me that it is working correctly. When I first start the car, it is running rich (black smoke out the tailpipe). When I press the accelerator before I start it, the choke goes completely closed as it should. However, even after driving it for quite a while with the engine temperature around 170°, the choke plate is still only maybe 1/4 open. On a warm day (air temperature 80° or higher) and with the engine temperature up around 170°-180°, I would think that the choke would be completely open. Am I wrong in this assumption? BTW, after it warms up, the engine runs smoothly and there is no visible black exhaust out the tailpipe.

I have tried moving the automatic choke adjustment leaner, but this doesn't seem to have any effect on the position of the choke plate. I can't turn the adjustment cover and get the choke plate to open any further. Any suggestions would be appreciated.

It is really great having this forum to ask my, probably inane, questions and get really helpful answers back!

Craig Duerling
Cambridge, Maryland

[35-709]

If adjusting it leaner doesn't help, the choke stove and related parts need to be disassembled and cleaned.  It is probably crudded (is that a word?) up and sticking, not uncommon at all.  Like everything else on these old cars, maintenance is the key issue.  When you disconnect the choke plate lever from the choke stove assembly the plate will probably operate freely and therein lies the tale. 

[Steve Passmore]

It could be the heat spring inside the choke cover broken or not connected properly?

[CraigD]

To report back, I took apart the choke and everything looked OK. The bimetallic spring was not broken. I gently turned a heat gun on it and it moved as I would expect it to. Everything seemed to be clean and free-moving. I put it back together and tried turning the automatic choke cover toward lean until the choke plate was just closed with the engine cold. It was almost a ¼ turn toward lean from where it had been set. I started the engine and it started just fine and ran smoothly. There was no black smoke from the exhaust pipe. I let it warm up and hit the accelerator, and the choke plate gradually opened and eventually, it dropped down from the fast idle like it should. I drove it to get it up to full operating temperature, the choke plate opened completely, and it ran great. So it turns out that the even though the choke cover had been set to about where it looked like it should be â€" this is the way the car came to me, it really needed to be turned much leaner for the choke to work correctly.

BTW, I found some great documentation on the Carter WDO carburetor at The Carburetor Doctor. The package contained Carter documentation and a “Packard Serviceman’s Training Booklet” that went into detail of how the carburetor worked as well as some specific details for the LaSalle. This was very helpful to me.

I know that this may seem pretty elementary to some of you, but it was a big deal for me. Thanks for your suggestions.

Craig Duerling
Cambridge, MD

[35-709]

Nice of you to write back with your outcome and a thanks.  All too often questions are answered here and the person who posed the question is never heard from again.  No "thank you", no "it worked" --- nothing.  Irksome at the least.

[Steve Passmore]

Nice of you to write back with your outcome and a thanks.  All too often questions are answered here and the person who posed the question is never heard from again.  No "thank you", no "it worked" --- nothing.  Irksome at the least.

Fully agree.