Stop in for a cup of coffee
This is what the check valve looks like when in place:
This spring loaded adjustment screw has a conical end that fits in a hole in the back of the check valve.
It goes in the other side (outside of carb) like so:
Then there is a flat plug pressed in over the screw to seal it.
In the last pic you can see one of the brass screws holding the choke flap is missing. Does anyone have one? I think the thread is 4-40?