MK25 EVO , IP adjustment (below 135psi)

[ladra]

Hello,

I have 6 MK25 EVO between my family and my sister's family that I service personally. I have noticed that most of them will not fall below 135PSI even with the adjustment screw all the way in (clock-wise).

Most are fairly new, less than 100 dives, couple of them over 100 dives. I service/clean them after 50 dives or so, complete break down, clean, and reassemble (reuse parts, only used new service kit couple of times). Yes, I don't have to do it so often but it's personal preference.

Besides changing the HP seat or the piston is there anything else that I can do to lower the IP? Yes, 135PSI is fine but I would like it to be 130, again personal preference.

I just had one that wouldn't go below 150psi, changed the HP seat and it's now at 135psi (lowest). Weird thing is that this particular one just had the service kit, so only about 30+ dives on the new HP seat. I put back the old HP seat and it went down to 135...

Are there any tips to lowering the IP for MK25 EVO, other than piston / HP seat swap?

Thanks in advance!

 

[Couv]

Have a look at these.

 

[ladra]

@couv ,

Thank you for the info..

As described in the maintenance procedure, "washers P/N 01.060.219 between the spring and the bushing (capsule)" can increase IP.

I was also advised the same from @Newdiv and @rhwestfall in another thread.

Thank you and much appreciated guys!

 

[Andrew Dawson]

Any update in finding a solution to decreasing MK25 IP pressure beyond the adjustment screw?

 

[abnfrog]

I find that the adjuster screw doesn't work all that well , when SP announced that they were changing the mk20 to an adjustable MK 25 I thought ..that it would be like the us divers type of adjustment . its not you still have to take apart the reg and adjust it like the mK 20 then fine adjust threw the adjuster .....

 

[rsingler]

There's one more kludge you can do to lower the IP, without changing the piston or spring.
Switch the existing HP seat oring from PN 01.050.147 (part #9 on the Mk25EVO diagram) to a metric 1.5mm cross section o-ring of the appropriate diameter, and 90 duro. This will allow the spacer (#39) to bottom out fractionally lower inside the HP compartment, thus pushing the seat slightly closer to the spring. A 1 mm cross section might do even better, but see below regarding the spacer.
This change is not authorized by Scubapro.
Also, switch the spacer 01.060.220 between the seat retainer and the body, to one of the shims used inside (01.060.219). That too, helps move the seat closer to the end of the piston, at least until the seat retainer and seat bottom out in the body.

 

[rhwestfall]

parts 28, 17 & 42, all of what are the EVO "upgrade", all result in cause IP to be higher.....

anything thinner in base thickness there will drop IP (though not SP sanctioned)

 

[abnfrog]

the o ring will work or just change it to a MK20, and take out the evo stuff

 

[Scubagaskets]

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