Need Vacuum help - 1973 318ci with a Carter bbd

[TaffetaMocha]

1973 Fury III with vacuum issues.

The car surges at idle and will have popping when cold starting and occasional misfires while driving.

Cold starting is also an issue.

I decided that I should simplify and delete what I can. What are the essential lines I need? And also how do I use a vacuum gauge?(I have one)

 

[Justin Plant]

The engine doesn't "need" any of it. I would block it all off, then add back the vital lines one by one until the engine starts to act up. Once it does, test that circuit for a leak. I'd start with the brake booster, then the vacuum advance and so on.
Good luck

 

[Toolmanmike]

1973 Fury III with vacuum issues.

The car surges at idle and will have popping when cold starting and occasional misfires while driving.

Cold starting is also an issue.

I decided that I should simplify and delete what I can. What are the essential lines I need? And also how do I use a vacuum gauge?(I have one)

I would check the choke and choke pull off operation because your issues start there. (cold start). When started cold, the choke butterfly should close fully with a push of the gas pedal. The fast idle can should pivot into position as well. As soon as the engine fires, the butterfly should open slightly and then continue to open as the engine warms up. A tap on the throttle will take it off of fast idle after a min. or so. This is all basic choke operation. I don't know how much you know or don't know about how a choke operates so that's why the education.

 

[Big_John]

First thing I would check is if the bolts are tight where the carb bolts to the manifold.

 

[CBODY67]

BEFORE you start ripping things apart . . . look for cracked vac lines first. Cracks might have happened over the years with age and vibration. Plus making sure the carb is tight against the intake manifold with a good gasket under it.

Basically, what you NEED for the engine to run well include: a vac hose to the vacuum advance on the distributor, a PCV line from the pcv valve, a vac source to run the hvac items inside the car (getting cold soon!), and a good vacuum source to run the power brake booster. The hoses related to the emissions canister and valving don't hurt anything and cost no power to operate, so they can stay. BUT if you might find small carbon granules i the float bowl, the basic canister probably needs to be replaced. The fuel tank is vented through the canister, too.

Is the carburetor idle speed and mixture adjusted to specs? Condition of the plug wires and spark plugs? Engine oil level?

Please keep us posted on you progress,
CBODY67