Problem with Poseidon x-stream

[IslandKraut]

I have noticed that this MK moniker fits the Jetstream better - while not official, in my mind I order them as such:
MK1 = 2960 Barrel first stage
MK2 = 3960 Flat Top first stage
MK3 = Xstream first stage

 

[rsingler]

^---- THIS

With regard to the OP, and @tbone1004 's spot-on diagnosis, that's a $70 part, plus service charges. Apart from your servo valve problem, the biggest reason that XStreams/Jetstreams breathe stiffly, is that IP is too high. These regs like an IP around 120.

 

[IslandKraut]

By the way - is there a way to convert a Jetstream to an Xstream?
Me thinks the nut is the same except that additional; hole, a new tube is ~20 bucks, and if one can get the plastic sleeve over the servo valve, it should be the same (yes of course get another mouthpiece tube, but those parts seem to be <100 bucks.