Martin - keeping the valve open is easy, I just use the lever in the
cockpit. Filling pressure is limited to a 1 meter head, but maybe
filling and dumping repeatedly will clear out anything in there. The
funnel has a fine mesh, so it's hard to see how junk could have gotten
inside the tank.

Bruno, Evan - unlike your tanks, my tank is plastic, so no oxide
worries. Getting it out is a little involved, but the maintenance
manual has clear instructions. That's a last resort, though. Sounds
like you may have no options, though, Bruno.

I'll check the cable tension leading to the valve this weekend. If
it's tight in the closed position, I bet the drip is due to cold
weather.

Meanwhile, anyone have any ideas on how to apply Vaseline to a valve
seat located some distance up an 8 mm tube?

-John