I don't know anything about these old engines but if the pipe attached to the manifold is open to drain, doesn't it affect the manifold vacuum or does it have a tap or one way valve? I'm curious.
there are no taps or valves.
But you tune it with the hole open and it is just another air supply ;although admittedly missing the air cleaner.
Thanks Chris, I'll have to get my head round that. So with the throttle closed, sucking fresh air. Like I said, I don't know anything about these old engines.
