I splurged and bought a Pilot Decimo with a fine nib recently. The problem is it puts a pretty heavy line down regardless of ink brand or formula. It's more like a German fine or Japanese medium! When I open it up , there is ink on the outside the nib unit. Cleaned it off, put it back together, checked it 10 minutes later and ink on the nib unit again. The converter is solidly in. Any ideas? It's still under warranty.