Bing carburetor problems?

Good evening, today when I was riding my Kreidler Florett k54, it simply died after a while. The fuel tap was also no longer working, so I installed a new one. Before, the fuel was sitting in the hose and wasn't flowing. When I pumped it with the pump, I couldn't hear any injection noise. After that, it worked perfectly; the fuel continued to flow, and I could hear the pre-pumping noise again. After a while, the idle speed got lower and lower until it died again and wouldn't start again. Fuel is still easy to pump in and it keeps flowing. What could it be? Thanks in advance!