Dived it this weekend and it worked great...except for a big hole that suddenly appeared in my mouthpiece causing me to suck in a bunch of water, lol. Thanks for all the help.
But, I do have one final question...what do the plastic bushings in the piston assembly do? As I said earlier, there were TWO in there from the factory. I only replaced one. And I notice that I have to crank down the IP screw all the way to get me to 130psi. If I add the other bushing, will that help me tune the IP down closer to 125 (should I ever want to)?
Two questions, first are you serious that a 'big hole suddenly appeared' in your mouthpiece during a dive? That's not a normal thing at all. If you're not just joking about it, then please inspect your mouthpiece before putting your reg back together after service. If you didn't remove the mouthpiece when servicing the 2nd stage, then you didn't do a good thorough job. The fact that you didn't know or bother to leak check it after assembly is another issue.
Second, about the bushings , YES it is important to replace both bushings, as well as as any other parts that came out of the 1st stage. Didn't you bother to look at a schematic, or at the very least take some quick photos of what came out of your MK25? Those bushings surround the HP piston o-ring and prevent extrusion, if they are the ones I assume you're talking about. They are very important. You should immediately dismantle your MK25, consult a schematic, and make sure that ALL the parts on that schematic are installed in the right place.
Usually I try to be pretty encouraging with self servicing your own regulator. It's not rocket science, it's not even particularly complicated. But you have to be careful and honest about your abilities and attitude about doing the best job you can. Sorry for the rant.
