I recently bought a Delta Colosseum with lever filling system. I had to return the pen because the pen wouldn't write. I cleaned the pen with water. I submerged the pen in ink and pulled out the lever. Kept the pen submerged to allow the pen to fill up. I cleaned the nib and started to write with it. I was able to write for maybe 1 minute. After 1 minute of writing, ink wouldn't come out of the nib.
I tested the filling system by emptying the pen using the lever. I used a paper towel to catch all the ink. I filled, wrote, and emptied the pen five times. Each time the pen would fill up and write for 1-2 minutes max.
What's the problem with the pen? Unfortunately, I don't have the pen because I returned it. The seller tells me there is nothing wrong with the pen. He tells me that I might be putting too much pressure on the nib. If I am putting too much pressure on the nib then why was I able to write with it for couple minutes.
What could have been an issue with the pen? Feed problems? It would be great if someone with a Colosseum could respond.