Duesenberg carb questions

Your friend was right, Chris, they are just larger, and green.

I guess 'frozen' was a bad choice. Locked in place would probably be better.

I once told a friend who's worked on many Js that I was intimidated by the engine. He said, "Nonsense, it's like any other old engine, just larger."

Not sure what the Duesenberg aficionados would have to say about that - - but the more I read things like this, the more I realize, it really isn't a complicated design for one so famous.

When the choke cable is pulled this disc is (per say) frozen in place, So when you are starting the engine (when cold) The choke cable is pulled and it sucks a large amount of gas for starting a cold engine. and is used only to start a cold engine. If needed to start a warm engine the engine is running to lean.
My 2 cents
Ken Clark

we're not in disagreement at sll. it just sounds like we are. I guess I was a little vague, as I didn't mean the plate was hooked mechanically to the throttle. you're wrong when you say it does not perform a choke function when the plate is frozen in place. all the air has to go through the bottom of the carb and as a result it travels at a high rate of speed, pulling more gas.

I've had fifty of those things apart and I agree, they're utter simplicity.

I would have to disagree with you on the operation of the Schebler carb. The hole you refer to on the bottom of the carb is called the fixed air opening and supplies air at idle and low speeds. When the throttle valves open and the motor demands more air the air valve on top of the carb, the three inch hole you refer to, is sucked open by the vaccum thus pulling the needle valves out of their bores and suppling additional fuel to the engine. A simple concept and it works well if set up properly.
CORDially Mike

This answer is a long time coming because I've been off the site for awhile.

The Schebler updraft carb on the early Duesenbergs would be very hard to do an air cleaner on, on either entry. The big one, on top of the carb, is a three inch (or so) diameter plate which opens in unison with the throttle. I've never seen one with an air cleaner. The choke freezes that air inlet plate and forces air to shoot up through the bottom of the carb at a high rate of speed, all the way up into the intake manifold.

The biggest problem I had with them was on museum queens. The cars would sit for months and the carbs would stick enternally and the air plate would stick open and lean the engine out terribly.

At that time you would have to get a five gallon bucket of carb cleaner, did-assemble the carb, soak it iver night, and re-assemble. Would run great for another six months or so. With some of the fuels, aircraft or racing, both leaded, it was not that big a problem.

When they changed to the downdraft carb one of the benefits was a horsepower increase.

The updrafts where the same carb. as L-29 Cord and some Auburns, but with a bigger 1 1/2" bore. No air cleaner used on L-29 or Auburn, so I suspect non on Dues. either.
CORDially Mike

When were the updraft and down draft cabs used? Do the updraft carbs have any air filter on them?

Thanks, Joel