Hi Martin

It already has clear fuel tubing sealing the needle, that is the only thing keeping air out. Sadly the needle is a very loose fit in the holder, you can wriggle it, and the end is blunt. The needle is also too long, it is almost out of the holder by the time a running setting is found,

Chasing a repeatable steady needle setting with this NVA is like chasing a rainbow.

To become a nice workable engine, it is my view that a replacement NVA is called for. I am thinking a Schlosser .25 NVA could be a candidate, or maybe one from the Peter Burford PB .33 They are available and affordable. I will think about it.