Removing the diaphragm from a second stage

[Couv]

But, yea, you want a screwdriver as wide as will fit.

See my review of Custom Scuba Tools precision fit driver.
Review: Orifice Installation and Removal Tool from Custom Scuba Tools

Contact @herman for further info.

 

[agilis]

I've gotten the things to pop off intact by moistening with moderately hot soapy water and blowing into the mouthpiece while blocking the exhaust.

 

[d^2b]

Thanks to everyone who chimed in. I think I managed to tighten the orifice (just the first 1/8 turn seems to have been enough to stop the freeflow). There is some play in the lever although not enough to rattle against the diaphram. I'm a bit unclear on how to actually loosen it. I can get a nut driver on it, but it just seems to spin the whole assembly. For now I think I'll declare victory as the freeflow is gone and the cracking pressure is still around 1.5". For the nylon orifice I have, I found the wide screwdriver on my victorinox cybertool (aka swiss army knife) worked reasonably well.