Hiker+ stuck valve

I have a Hiker+ that hasn't been used for a long time. It was stored with fuel in the tank. Now, the valve is stuck shut. No air goes in when pumped. I've linked to a video that shows the problem. How can I fix this?

https://youtube.com/shorts/a1xznPfYboI?si=LgPNQRYAuQQoefVV

 

Valve or pump or both? You don’t make sense. Leary of the link.
Duane

 

Air is compressed when I press the pump, but none goes into the tank. The video shows the pump coming back out after each press.

 

Take out the plunger, pour some kerosene (fuel) in the pump tube. Put plunger back. Push the kerosene through with the pump.

 

It worked. Thank you!

 

Glad it worked. Fuel is less compressible than air, so it forces the non return valve open.