I posted a similar problem a couple days ago called "DSV Oring Problem" that no one has commented on yet. I believe it to be opperator failure. I use it several times every dive, and never re lubed it. The oring stretches when I open/close it, causing the oring to pop up and pinch in the gate?. I solved it for now by greasing the oring and entire area the oring slides against. Normaly I would just make the oring shiny, but the mouthpiece oring has a long way to slide on plastic that has gotten scuffed up prety good. Look in your mouth piece with a light and see if yours is coming out of the groove. I plan on cleaning and greasing mine more often.
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