Re: 1950 327 with Ultramatic - Idle Speed

Posted by HH56 On 2023/2/6 17:28:13

Disagree Don. The passage the ball works in is connected at the top to vacuum via passages inside the carb so the bottom needs another opening so the vacuum could have something to pull. If both ends were connected to the manifold both would have vacuum and nothing would happen. In this case the bottom end is left open to air and there is a screen inside to keep any debris from being sucked into the components.

As soon as the engine starts vacuum is present at the top of the passage and when the accelerator is released by the driver the ball is sucked up away from the throttle shaft breaking the mechanical connection so the accelerator can no longer activate the switch. Ball is pulled tight against a machined seat in the passage and is held there to seal off any farther air flow until the engine stops and ball loses the ability to stay up. It then drops down and everything is set up to be ready for the next start.