Info Servicing Scubapro MK2

[DR3AD]

It depends on what the supply pressure was when the IP measured 127psi. If it was 3000 (i.e. full tank), then that's pretty low. If it was well under 1000, that's in the range. Since the MK2 is an unbalanced piston, IP will drop 15-20 psi (I can't remember exactly) between the supply pressure of a full and near empty tank. So a good tech will set it on the high end with a full tank. I think mine is around 145 at full, and that way it doesn't drop below 125 when the tank is close to empty.

If the IP on your reg is 127 with a full tank and it was just serviced, that tech didn't do his job very well. It will work, but with an unbalanced 2nd stage it's not going to breathe very well at low tank pressures. Someone, either you or that tech or a different one, needs to add shims under the end of the spring to bring the IP up so that it stays within 125-145 psi throughout the whole supply pressure range.

There is a little problem with doing this after the fact; that HP seat now has a small groove in it from being pressurized, and you have to take it apart to put the shims in. Then when you put it back together, the groove might not align perfectly with the sharp edge of the orifice (that's the part that cut the groove) and you might get a little IP creep. It might be fine. If it was mine, I would try adding shims, and if that fixed the IP and also didn't cause creep, I'd count my blessings and dive with it. If it started creeping but the IP was good, I'd take it apart again and replace the seat, they are not expensive and they last forever.

This is why a good tech will measure the IP before rebuilding, to be able to make a good guess about how many shims to use. Sometimes the reg creeps so badly you can't really tell, but usually you can. It is a little bit of a guessing game.

Thanks that makes sense. Will make my own IP gauge and test myself on a tank.

 

[SaltyWombat]

@nikolay_zhelev, can you tell us what ultrasonic cleaner you have? It did a great job.

 

[nikolay_zhelev]

@MolaSquared I'm using Tickopur R27 concentrate. The solution I use for ultrasonic cleaning is 5% Tickopur R27 dilluted in 60°C warm water. The result is great, but the product is not cheap. It's based on phosphoric acid as you might guess.

All the best!

 

[SaltyWombat]

@nikolay_zhelev , I mean which ultrasonic cleaning machine do you have?

 

[nikolay_zhelev]

Skymen Cleaning JP-020S. Mine is without drainage valve, but I would strongly reccomend you to get one with valve.

 

[DR3AD]

Happy to report that i know have 4 dives on the mk2 that i did get (only ended up purchasing a single one) andi am very happy with it. paired it with some new SP second stages R195 for both and It works very well. Not trouble with the breathing effort, I have been down to 16m (OW allows only 18) so far with no problem.