[Mg-t] SU Carb Question

[wbeech at flash.net]

Helping a friend re-build his H2 carbs on his TD and after disassembly I
noticed that the ring on top of the body, after removal of the piston/slide,
has two screws and two holes that vent to the outside of the body. On one
unit of these the holes have been sealed up with JB-Weld(?) and the other
unit has the holes open to the atmosphere.

http://www.flickr.com/photos/7899895@N08/6578318551/
<http://www.flickr.com/photos/7899895@N08/6578318551/> 

So, inquiring minds want to know, should these be sealed up or left open?

TIA for all the help!

Bill