Ahhh, the ol TQ. They're awesome when they work. The problem is the phenolic body/ bowl. They get out of shape and internal leaks happen.
The metering system is exactly like an AFB. just behind the primaries going across is a thin "tree" and on either side between the bores are wells with the metering rods. The middle of the tree is the plunger, and that makes the magic. There's also a secondary adjustment.