Where do vacuum lines go from carburetor?
It should connect to the petcock next to the fuel line. You should see a smaller fitting usually on the front of the petcock with a round housing behind it. This is where the vacuum diaphram is. Engine vacuum turns on the petcock to deliver fuel to the carb only when the engine is running.
What does the vacuum line on an intake do?
The intake is under vacuum when not in boost – that is what the PVC that is mounted inside the intake manifold controls and pulls crankcase vacuum when the throttle is lifted. In boost, the PVC prevents pressure from entering the crankcase port from the intake manifold.
Should I hook up my vacuum advance?
Plugging your vacuum advance into a direct source will allow it to engage at idle, which is good for a number of reasons. Much like cruise conditions, engines run leaner at idle than they do under load. Again, this means the mixture burns slower and needs an earlier spark to optimize the burn.
Does a vacuum leak affect idle?
1. Sporadic Idling. A vacuum leak introduces excess air into the engine, and this directly affects how your engine runs. One of the primary signs of a vacuum leak is sporadic idling.
Where is ported vacuum located?
End of dialog window. Ported vacuum is vacuum that is low at idle and increases as you give it gas. Attached to your distributor it will cause the vacuum advance to move quickly to increase performance and drop off when you let off on the gas for a smoother idle. Ported vacuum is taken from above the throttle plate.
Is vacuum advance needed?
You need the vacuum advance for best performance at low throttle settings for the street as Barry said. If you were running on a circle track or a drag strip there wouldn’t be a need for it because the mechanical advance would be doing the job.