Acetylene valve leak?

[ksilinux]

When using leak check solution, shake bottle and apply bubbles at area your checking. Check regulator diaphragm vent holes around between pressure adjustment screw and diaphragm. Apply bubbles at holes before opening cylinder valve.

I have never seen bubbling leak detector solution at threads retaining regulator to cylinder valve. But have seen bubbles at hole on back side of swivel nut away from threads.

Some regulators had relief valve screwed into regulator port to protect LP pressure gage now some regulators have hidden internal relief valve.

Illustrated parts breakdown are available on Victor web site.
http://www.thermadyne.com/victor

Eh, I did all that and was not able to find anything...

It is not a leak, it is something like a second long puff. I open the cylinder valve, hear a hiss, smell acetylene and second later everything stops and I can work all day without problems.

I did apply the leak detector solution everywhere and was not able to find anything. It is possible that initial puff simply blows it away from the leak location faster than it can form a bubble that when it stops some excess liquid flows back to that location and I see nothing.

Nothing leaks after couple of seconds after valve opening. Everything is tight, no leaks, no hiss, no smell.

And it is definitely that VTS-460A regulator to blame because I have never had any problems with the older Powr-Kraft one on that same setup. Nothing changed, I just replaced my good old Powr-Kraft regulator with VTS-460A. Same cylinder, same hose and torch.