Pre-war (up to 1942) 1939 Cad Lasalle Carburetor butterfly not opening fully.

[ricardo_padilla]

The lasalle 322 engine quit running. I noticed the carb butterfly somewhat open; but, not fully (see picture with mirror).
Question:
1 - Is the top carb butterfly suppose to open just a little? Some one assembled the carb incorrectly?
2 - What is the function of the left knob on dashboard (the black one on picture). Seams to control the butterfly, just a small amount of travel.

[harry s]

Looks like the factory automatic choke has been converted to manual which is fine as long as it can be opened all the way after starting and the engine and it begins to warm. The black knob in your picture seems to be the control for the choke. If you can adjust it to where it opens the butterfly all the way it should solve the problem. If it can't be adjusted you may need a new cable that has more travel. As a test you can disconnect the choke control at the carb and see the engine continues to run.    Harry

[dn010]

Doesn't look like there is anything securing the outer portion of the cable near the carb so that it won't move. When you're using the control knob like this, the whole thing is probably flexing at the carb so it is not opening/closing the choke properly. Looks like there may have been something rigged up to hold it down against the manifold but it's hard to see in the photo.

[39LaSalleDriver]

I wouldn't want to comment on whether there is anything wrong with your carburetor without fiddling with it personally. However you should at the very least be able to push the butterfly into the 90 degree position with your finger if all is well.

On the other hand...unfortunately someone has drilled a hole into your dash at some point to install what appears to be an aftermarket choke cable (the black knob you're asking about). If you look to your radio panel, at the bottom is a control marked "THROTTLE", that is your manual control for the carburetor. If there is any life left to it (I suspect many of them have been broken over the years but are restorable), it should pull/push out/in to control the arm on the side of your carburetor. As dn010 vaguely referenced, there should be a clamping bracket mounted to the exhaust crossover which holds that sheathing stable so that the cable can actuate forwards and backwards. Here is a photo (not of my car) which shows this arrangement. 

[Tom Boehm]

To sum up the previous responses, the choke control on a car controls the choke plate at the top of the carburetor. This controls the amount of air going into the carburetor. Your car originally has an automatic choke but someone added a manual choke. The throttle control controls the throttle plates at the bottom of the carburetor. The throttle plates control the air/fuel mixture going into the engine. This dashboard throttle control is in addition to the gas pedal, which does the same thing. This dashboard throttle control could be used as a primitive cruise control. That seems dangerous to me.

I don't know the actual reason for the dashboard throttle control. The factory owners manual and the authenticity manual don't tell how to use it.

[ricardo_padilla]

Thank you for your input! I am starting to develop confidence in dealing with issues with this Caddy!

1 - The black knob (manual choke) now works, by having the set-screw moved below the limiting stub (see picture of screw). This allowed for a fully open butterfly, and the black knob now works. The wire was not rusted in place, did some lubrication of the cable. Needs a better cable wire holder.

2 - The throttle control is rusted in place, cable needs to be replaced, and proper cable clamps/holders installed (throttle cable was held in place by simple steel wire twisted over the exhaust x-over).

Found plastic drill shavings inside external NAPA fuel filter (see picture), restricting flow, removed fuel tank, tank was clean (amazing). Time to flush lines and new filter.

I need the coolant steel intake pipe on top of the heads. I can not find them, they have heavy rust build up. Suggestions for removal or replacement?

[Tom Boehm]

The throttle control is not necessary for the proper running of the car. That can be a lower priority repair. if you soak that cable in Evapo-rust it might loosen up. It may take weeks but you have time because it is not necessary. It is not easy to recrimp or attach a new cable at the knob on the dashboard.

I replaced those coolant necks on my car about 5+ years ago. They were reproduced. I think I got them from Allcads of the '40's/50's. I looked on their website but did not see them. Call them and check. They are not hard to change. Are yours leaking? If they are not leaking then rust on the inside is OK. Mine were weeping coolant through the metal. Post a separate question in the technical section about who sells reproductions.

[Tom Boehm]

FYI: Notice the head bolts holding those coolant necks on are different from the rest of the head bolts. Don't mix them up with the other head bolts. They are a different length and could damage the block if used in a different hole. It is not necessary to remove any other head bolts when changing the necks but I thought I would mention the difference.

These are not hard to change. Just drain the cooling system. There is a paper gasket under them.

[39LaSalleDriver]

To sum up the previous responses, the choke control on a car controls the choke plate at the top of the carburetor. This controls the amount of air going into the carburetor. Your car originally has an automatic choke but someone added a manual choke. The throttle control controls the throttle plates at the bottom of the carburetor. The throttle plates control the air/fuel mixture going into the engine. This dashboard throttle control is in addition to the gas pedal, which does the same thing. This dashboard throttle control could be used as a primitive cruise control. That seems dangerous to me.

I don't know the actual reason for the dashboard throttle control. The factory owners manual and the authenticity manual don't tell how to use it.

Thanks for the correction Tom. I'll admit the mysteries of the carburetor are a bit outside of my skill set and I should learn more about their intricacies. I had my carb professionally rebuilt so I really haven't had any issues in that regard that would require me to do an in-depth study of their workings. I've never had the need nor interest in studying how a choke knob would work, so I based my response on what I knew was supposed to be there re: the throttle control.

I have experimented with using the throttle control as a "cruise control". It works, but wouldn't recommend it with modern roads, nor am I sure I would have recommended it back in the era either. I use mine to increase my idle when I first start my car after it has been sitting for a while. It tends to run mildly rough on initial startup in that scenario. I like to let the engine warm up some before I pull it out of the drive, and that control allows me to set it and go do other things like clean the windows &c. Then when I'm ready to go I push it in and all is well.

Since I recast all of my plastic parts, I had the luxury of being able to take a brand new choke cable and affix it somehow to be cast directly into the resin for my throttle control. I don't exactly remember how I did it, but I think I might have attached a threaded piece onto the cable and then cast a corresponding nut into the resin. It's worked out great for me.

Those coolant outlets are, or I should say were, available from McVey's. I don't think they have them on their website, but you should be able to call them to confirm. I toyed with getting a set last year as mine are functional now, but I could see them needing to be replaced somewhere down the road. They've rusted thin towards the output end and have already lost I'd say 1" of good material, but I don't exactly know.