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Author Topic: 59 cdv runs rich  (Read 796 times)

Offline Paul

  • Pscarlato
  • Posts: 184
  • Name: PScarlato
59 cdv runs rich
« 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.
‘59 Caddy, Seminole Red with Dover White top

Offline Joe Jensen

  • Posts: 71
  • CLC Number: 32536
  • Name: Joe Jensen
Re: 59 cdv runs rich
« Reply #1 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

Offline Omarine

  • Posts: 256
  • CLC Number: 32411
  • Name: Oscar Marin
Re: 59 cdv runs rich
« Reply #2 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
1949 Harley Davidson FL
1952 Cadillac Coupe de Ville
1961 Chevy Impala 2 dr hardtop

Offline Paul

  • Pscarlato
  • Posts: 184
  • Name: PScarlato
Re: 59 cdv runs rich
« Reply #3 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.
‘59 Caddy, Seminole Red with Dover White top

Offline 35-709

  • Posts: 5348
  • The most valuable antique is an old friend.
  • CLC Number: 4719
  • Name: G. Newcombe
Re: 59 cdv runs rich
« Reply #4 on: November 21, 2021, 02:21:58 PM »
New carb --- could very well the jets need to be a little smaller.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Offline bctexas

  • Posts: 218
  • CLC Number: 31627
  • Name: B Long
Re: 59 cdv runs rich
« Reply #5 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!
 
1965 CDV
1970 SDV

 

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