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Carb seems overly rich at low speed/idle.Previous owner (deceased) must have worked on it as there was a mixture screw assy in glove box. Does this use an enricher like on SU carbs? Plugs and tail pipe sooty and smells rich. Bought new plugs today just because. Also would like a replacement inlet fitting. Looks like someone tried to hold it with pliers and carb side is no longer round . Was leaking but found a square ring that seals it.

There should be a T-handle adjustment fitting on the bottom of the carburetor. That adjusts the idle mixture. Fully warmed up, turn the T-handle clockwise (looking from underneath the carburetor upward) till it starts to miss, then counterclockwise until its running smooth.

The carb does have an accelerator pump. Keep in mind, the rich nature of your carb might be a function of float level too, which should be checked.

Consider posting a picture of it.

Hi,

Is it original or one of the reproductions as I have the same on my 733 which I replaced on mine as the original had deteriorated.

Gene

My carb is original. How does the choke work? Could problem be there? Car starts easily, couple of rr,rrs and its away hot or cold. Looks like T turn has been changed as there is one in glove box. Previous owner has passed so I can't ask.
Car is original and unmolested. I am 3rd caregiver. Is licensed and I want to drive it without gassing everyone.

What exactly has replaced the T-handle adjuster? What is there now?

The T-handle is what you should see coming out of the bottom.

pac-carbs.com/collections/carburetors-1/products/metering-valve-complete

I suggest you send it to Scott at Pac-Carbs and have him go over it. He is a great guy and will replace the necessary parts and make it like new. He also test runs it on his engine to make sure it is ready to go. I have one of his new reproduction 51's on my 32 and it is a work of art and the car runs like new.

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One last thought is to make sure the butterfly flaps that move the metering jet up and down are working, and not stuck. My carb had sat for many years and were stuck in position and not able to move the metering jet. Once I got things lubricated and working as they should, everything ran much better.

The DL 51 is a very interesting design. Only used about 4 years on premium brands (Packard, Graham, Cadillac). Every car show flea market I go to I hope to find a big cardboard box full of them.

The T turn was replaced (I think) as there is another one complete with gland nut with new packing in it in glove box. Is there a good parts drawing somewhere. I am trying to get my head around its internals. What I would like is the banjo fitting between the fuel line and carb. It is slightly squashed and the SAE taper is beat up. Not leaking now but it was. I am new to this game and have no contacts for parts or service. How does the choke work?

I believe the choke works by it cracking open the throttle plate a tad, then permitting a dedicated port to allow raw gasoline to enter the venturi. It is not like an SU where the jets drop, and there exists a puddle of gasoline to achieve a rich mixture.

PM me your email and I'll send some files that I've collected along the way