My Origianl 65 Caddy Fleetwood Brougham with 56000 Miles has had a
rough idle since I purchased it 6 years ago. It has the Rochester 4GC
Carb and an "open PCV" system.
So for this has bee driving me up the wall.
I have rebuilt the original Rochester 4GC Carb 3 times with 3
different kits, with a little benefit to the rough idle. Problem is
the kits are the "One Size Fits All" Rochester 4GC and has many
gaskets that are for specific applications. I used the Throttle Body
to Base gasket like the one that came off, but I don't konw if the
carb was previously rebuilt.
The Barb Base to Throttle Body Gasket has some passsages called" Vapor
Vent Passages,' both on the primary and secondary bores. Other
gaskets did not have these on the primaries, but they would not fit.
There was still the rough idle.
I then changed the plugs, wires, dizzy cap and rotor, condesor,
points, checked the dwell and timing. All seems to be up to snuff.
Still no difference.
So I got a Crane Fireball XR1 Ignition Module, which fits in place of
the points and condensor, automatically setting dwell. No difference
Covered ALL the vacuum lines leading to the carb and the intake
manifold. No difference either. HUMMMMMM
Bought a Professionally rebuilt Rochester 4GC, which made a slight
I am at my wits end with this idle problem!!!
I know that the Choke Heat Tube that runs through the Intake manifold
is rusted throught, but have been told that it wouldn't have any
influence on the idle. I am not sure if they are correct on this as
they aren't a mechanic.
So I don't know if that is true or not.
Also, I think the rebuilt carb has the vapor vent passages on the
primary bores as well as the secondaries.
I am hoping to find someone who really knows 65 Caddilacs and/or
Rochester 4GC Carbs to help me out with this situation, as I would
like my car to idle like a Caddy should. Nice and smooth.
Anyone able to offer any help???