Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: Paul on November 20, 2021, 06:58:30 PM

Title: 59 cdv runs rich
Post by: Paul on November 20, 2021, 06:58:30 PM
Hello! My 390 seems to be running rich. The exhaust is strong. I've adjusted the idle air screws correctly. The engine idle is smooth. Am I missing and adjustment somewhere that could lean out the mixture—or do old cars just smell this way? Thank you.
Title: Re: 59 cdv runs rich
Post by: Joe Jensen on November 20, 2021, 07:32:23 PM
I would check your spark plugs and see if they are dark with soot to confirm you are running rich.  Aside from the mixture screws you could have a situation where the choke is not full opening when warm.  You might just try backing off your choike adjustment.

You could have issues within the carburetor itself which you couldn't discover without rebuilding it.

Good luck!
Joe
Title: Re: 59 cdv runs rich
Post by: Omarine on November 20, 2021, 08:48:42 PM
The carter 2 bbl on my 52 cdv was running rich a few months ago and it wouldn't lean out even with screws all the way in.

Turned out float was so high, it was letting fuel spill into the venturi while idling. Corrected the float and that solved the issue....

Cheers
Oscar
Title: Re: 59 cdv runs rich
Post by: Paul on November 20, 2021, 11:44:34 PM
Appreciate the thoughts on this. The carb is new. It's an edelbrock similar to the carter version. Works well. I will experiment with leaning the choke.
Title: Re: 59 cdv runs rich
Post by: 35-709 on November 21, 2021, 02:21:58 PM
New carb --- could very well the jets need to be a little smaller.
Title: Re: 59 cdv runs rich
Post by: bctexas on November 21, 2021, 06:00:58 PM
Hi Paul,

My '65 CDV came to me with an Edelbrock 1406.  The 429 ran pretty well overall, but at cruise it had a subtle twitch.  I picked up a tuning kit from Edelbrock, and switched the metering rods to 1 step richer.  Cleared it right up - the car now runs great.  The metering rods and jets can be changed with the carb on the car in just a few minutes.  Edelbrock also has clear instructions as to which parts cause the mixture to change in which direction and how much.  With a bit of fiddling I suspect you can make it run well, assuming a healthy engine and ignition.

Happy Motoring!