I have that same carburetor on my 1974 Malibu, and it runs pretty good. The choke is not connected on it either. I believe that the choke coil was heated by a tube that went through the intake and into the head. The hot air from the tube would heat the coil in the choke. The tube connected to where that orange cap is on your carb. Your probably best to find the correct one for your Buick, though. You'll also need the coil assembly and arm that mounts where that plate is covering the intake, under the existing coil on that Oldsmobile carb.
Found this video that shows how these hot air chokes are supposed to work and now I can clearly see that I am missing a few parts! Ignore the Mopar logo in the video!
It also looks like I have a vacuum line connected to the back of the carb where in the video he says this is not a vacuum line. I have mine circled in blue in the images below, I will need to trace this line and see where it goes. What is the port that I have circled in red, I would assume that is a vacuum line?
I have seen an electric replacement for sale at Everyday Performance... I would be way out over my skis trying to install it! http://www.everyday-performance.com/electric_choke.htm
The vacuum line at the rear of the carburetor normally goes to a vacuum storage container that operates the climate control doors. There are two types of vacuum available at the carburetor. Manifold vacuum and ported vacuum. Manifold vacuum is sourced from BELOW the throttle blades. Ported vacuum is sourced from ABOVE the throttle blades. Pretty easy to tell the difference. If you remove a vacuum line from the carburetor while the engine is running at idle, and it hisses loudly, that is manifold vacuum. If you hear nothing when you remove the line, it is probably ported vacuum. Ported vacuum is non existent at idle, but increases rapidly as you open the throttle. You can feel the suction from a ported vacuum connection with your finger as you open the throttle. Leaving a manifold connection open will cause a vacuum leak that will impact engine performance by leaning the mixture. Leaving a ported vacuum connection open will be inconsequential, it will just introduce unfiltered air into the engine, but will not affect fuel air mixture.
Larry, so I would assume the blue circle in my picture is a ported vacuum and the red circle is a manifold vacuum? And it would follow that the manifold vacuum being open like that is not good? Thanks!
No, the exact opposite. Just start the engine and let it idle. Pull the blue one off. It will probably hiss and stall the engine if it is manifold vacuum. Test all the vacuum nipples on the carburetor.
When converting to electric. Omit gasket behind original hot air choke. Electric uses body of carb as a ground. Also should pull choke housing and plug vacuum passage the hot air uses. Or atleast find a tight fitting cap to go over original hot air source on choke housing.
I am not sure the Everyday Performance unit will work on this carb? I think those are engineered to fit on the old divorced choke carbs. I think personally, figuring out which manifold you have (since that somewhat dictates the choke), or taking the carb to someone who can install an electrically heated coil are the simplest solutions? Or there is this item, which changes your carb over to an electric choke... https://quadrajetpower.com/electric-choke-conversion-kit/
The fitting in the rear of the airhorn is to supply fresh air to the intake manifold heat tubes so ALL the air to the "hot-air" choke is filtered. It is NOT a vacuum supply. Converting a "hot-air" choke carb to electric is an easy conversion. I sell an electric choke that is USA made and works like it's supposed to. Been selling them for at least 20 years. They "clock" with the terminal in the down position like they are supposed to so it looks correct and doesn't hit factory or drop air cleaner bases. It comes with instructions, and a connector to wire it in. The best place to pick up 12 volts from a key-on ignition source will be at the wiper motor. I would not wire one into the wire to the coil or HEI. https://cliffshighperformance.com/product/electric-choke-and-pigtail-connector The factory started using electric chokes in 1975 and continued phasing out divorced and "hot-air" chokes from that time on. Electric chokes are a nice upgrade because they work independent of engine heat from the intake exhaust cross-overs. So you can have a working choke even if the cross-overs are blocked off, or using an aftermarket intake that doesn't use them. It's also a nice upgrade from stock set-ups as more times than not the factory heat tubes are rusted, leaking, or missing.......Cliff
