1960s 1964 Cadillac Carburetor

[Erikgooding01]

Hi there, my name is Erik, I am 22 and this is my first post so please forgive me if I make some mistakes. I have a 1964 Cadillac Coupe Deville and have recently started having some problems with the carb. I have the Rochester 4GC carb and the car was flooding itself after driving for about 15 minutes. So my Dad and I took apart the carb and noticed that the fork on the primary float was broken so naturally I found a 25 dollar donor 4GC on eBay to get another one. When it came in I replaced my float with the new one and measured and bent everything to specs that I found in the Cadillac book and from a Rochester diagram. So I put it all back together and noticed the idle speed was a little rough and the car was shaking more than usual in park and in drive. I then drove the car around at cruising speed the RPMs were very smooth and it felt like normal but I noticed that on accelerating from stop it was delayed. Then when I got to speed and held the accelerator at a constant speed it would bog down and then pick up again. I then tried to play with the idle mixture screws as well as the idle air bypass screw to no avail. Then I replaced the new float with the old broken one and it fixed the bogging down issue but it still idles rough and hesitates a little bit on starting from stop. Any suggestions I am open to! thank you

[Clewisiii]

Have you checked for vacuum issues. Vacuum advance and dash pot.

[Michael Petti]

Make sure the carb to manifold and intake manifold to block bolts are torqued to correct spec. Non of the regular tests found a vacuum leak in my 60 390, but they were a bit loose and drivability improved a lot after I torqued them down correctly. Another suggestion is to get two cans of Seafoam. One for the tank and the other for the carburetor. Use according to directions. Let us know of your progress.

[jwwseville60]

I like original carbs so dont get me wrong, but I have great success on my 63's and my 64 Eldo
with Edelbrock. They are designed to run on ethanol fuels and parts are easy to find.
I keep the originals in a box, rebuilt.
The Eddies mimic the originals pretty well in looks.

I keep six ounces of Marvels in a full tank.
This helps with any water issues and mimics 1964 gasoline which had more
lubricants in it back then.