MK25 EVO, IP adjustment screw # of turns

[ladra]

Hello,

Quick question regarding the IP adjustment screw.

As stated in the Service Manual, it only turns about 1.5 turns smoothly/freely. However, you can/could "force" it to turn more, clockwise.

Question - Screwing in more than 1.5 turns by force will damage the HP seat, correct?

I'm guessing it'll drive the seat into the knife-edge of the piston?

Tried it with an old HP seat, turned about 1/4 more, and it did drop IP from 150psi to 142... But I'm guessing it's not a good idea to use it that way.

As always, appreciate your feedback.

 

[axxel57]

No, you won't damage the seat (at least not the seating area), but with too much force maybe the screw.
There is no way you could screw the seat onto the knife edge of the piston.
The seat is blocked by a landing (right word?) in the 1st stage block......
What do you want, increase or decrease the IP?

 

[ladra]

@axxel57 ,

Thank you for the informative reply. I am usually trying to decrease IP.

Sometimes lowest I can get to is around 145ish with screw in all the way. When greater than 145, seems like only option is to change the seat.

 

[axxel57]

Strange!
I have more often the problem to increase the IP.
To decrease, remove the shims and make sure that the spacer is on top of the HP seat.....

 

[ladra]

Ha ha. That is strange.

Correct, no shim under string and metal spacer on top of the HP seat. Weird thing is that these two MK25EVO are fairly new, less than 50 dives.

I gonna swap springs with one that requires a shim and see if that helps.

Thanks again!

 

[Andrew Dawson]

Any luck in finding a solution to this problem with IP being to high and not able to readily adjust it below 145psi?

 

[buddhasummer]

I'm sure you know this but just in case, adjust ip unpressurized unlike diaphragm regs, or you can cause damage.

 

[Couv]

Any luck in finding a solution to this problem with IP being to high and not able to readily adjust it below 145psi?

@Andrew Dawson and @ladra Did you ensure there is a spacer between the adjustment screw and the hp seat? If yes, then try removing the washer under the hp seat retainer.

 

[ladra]

@buddhasummer ,

Yes, adjustment is made when depressurized. I believe it's nearly impossible to turn the screw when it's even little bit pressurized, I haven't tried though.

@couv ,

Yes, there is a metal spacer between the adjustment screw and the HP seat. I will try removing the washer under the HP seat retainer next time I service, probably in a month or so.

Thank you both!

 

[ladra]

@Andrew Dawson ,

For me, using a new HP seat lowered the IP to "normal". Weird since the "old" HP seat was fairly new.