Floor pump problem? Blackburn Air Tower 4

[MinnBobber]

My Blackburn is acting up:

Fills the tube fine BUT does not stabilize. Blow back air pressure causes the handle to shoot up.

What is the likely fail?
Is there a worn valve in pump head??

Thanks

 

[Comfortably Numb]

Is the valve in the tube stem stuck, that is, not seating? That’ll do what you describe.
I always had the same issue with small hand pumps bending presta internals causing them to jam. I prefer Schraders for durability.
CN