[C320-list] Galley Sink Won't Drain

[Timothy Osburn]

My galley sink won't drain.  I assumed there was a clog in the hose but
when I disconnected it yesterday I surprised to find that the problem was
with the seacock ( ..and yes, the seacock was open ) and the hose was
fine.  The manual basically says that there are no serviceable parts on the
seacock.  I opened and closed the valve several times because repeating the
same behavior while expecting different results is....oh,never mind.

Anyway, I'm assuming that there is either some growth on the bottom that is
obstructing the flow or the valve itself is whacked.  If it's the latter,
is there anything I can do other than replacing it?  What does the little
white pen in the middle of the valve do? Anyone else have this problem?

Thanks!