[6pack] Leaking Stromberg

[TR6UO at aol.com]

I smelled gas at startup yesterday and traced it to the forward Stromberg.  
It appears to be coming from the bottom. Is that an O-ring? The last carb I 
 repaired was on a 4A some years ago.
 
What do I need to do here? Does the carb need to come off or can this be  
repaired in place?
 
Thanks for any help!!
 
Steve
'72 TR6