IP too high? or?

[olphart]

Just had my MK17 serviced and it seems to feed too much air on inhale. It feels like it's pushing air in and the excess comes out my nose into my mask. This is great for keeping water out of the mask, sort of an autoclear, but not what I want to see with my sac already too high. I checked the IP at the 1st and it's 140 and locks up every time, so there's no creep, but something's not right. Adjusting the predive lever has no effect on this. Both 2nds show the same characteristic, so I doubt that the problem is in the 2nds.
Also, neither freeflows any more readily than it should
Any ideas??

 

[Diver0001]

If the IP were too high it would free flow. You're reg is just a high performance reg and tuned very well to provide the best work-of-breathing it can.

In short it is unlikely that there is anything wrong with your reg.

That's separate from the issue of whether or not it feels right. If it feels like it's breathing "too easy" or even breathing positive then there are ways you can "de-tune" it slightly to where it feels right for you. Both the 1st and 2nd stages can be adjusted to increase the work of breathing. Without going into a lot of detail, either the IP of the 1st stage can be reduced, which might not be a bad idea given the cold conditions where you dive or the tension on the poppet in the 2nd stage can be increased.

One thing you can try before taking it in is to set the venturi from "+" to "-". It could be that the assist from the venturi is acting as more a nuisance than a help in your case.

R..

 

[rhwestfall]

also, try to "sip" vs, "gulp".

 

[redacted]

That sounds more like a performance characteristic on the 2nd stage(s). The venturi effect is adjustable on many 2nds. What ones are you using?

 

[halocline]

Just had my MK17 serviced and it seems to feed too much air on inhale. It feels like it's pushing air in and the excess comes out my nose into my mask. This is great for keeping water out of the mask, sort of an autoclear, but not what I want to see with my sac already too high. I checked the IP at the 1st and it's 140 and locks up every time, so there's no creep, but something's not right. Adjusting the predive lever has no effect on this. Both 2nds show the same characteristic, so I doubt that the problem is in the 2nds.
Also, neither freeflows any more readily than it should
Any ideas??

What 2nd stages? The predive lever is something I associate with D series 2nds. Is that what you have? This sounds like a venturi assist issue, and IMO most newer SP high performance 2nds have too much for my tastes. It is true that a lower IP should lessen the venturi assist effect, so you could try setting the MK17 to 125 and see how that works for you. But, you should be able to adjust the venturi at the 2nd stage, even with D400s.

 

[tbone1004]

IP is fine. Probably a smidgen high if it is truly 140, but that's within the accuracy range of most IP gauges, so as long as it is locking up it's fine. Which second stage are you using? Sounds like the tech may have set it a little too light cracking pressure, but most people like them to basically breathe for you. Your first stage is fine though

 

[eelpout]

If the OP would tell us what 2nd stage you have on your MK17, it would help. Based on the information you posted your 1t stage in functioning as it should if it locks up at 140. The adjustments to take care of your problem is on the 2nd stages. The unless you have an older 2nd stage, there should be a way to adjust the spring tension and the distance the diaphragm has to travel before opening the valve.

 

[olphart]

If the OP would tell us what 2nd stage you have on your MK17, it would help. Based on the information you posted your 1t stage in functioning as it should if it locks up at 140. The adjustments to take care of your problem is on the 2nd stages. The unless you have an older 2nd stage, there should be a way to adjust the spring tension and the distance the diaphragm has to travel before opening the valve.

The 2nd is a Zeagle that came with a flathead 6. The octo is an old Seaquest.

 

[LeadTurn_SD]

Does the Zeagle ZX (probably the 2nd stage that came with the Flathead 6) freeflow at all when not in your mouth? What I mean is does it slightly "hiss" when there is no back pressure, or does the problem only occur when breathing from it (and the other 2nd stage).

It sounded from your description that the 2nd stages might have tuned to a lower IP, and that they were as a result a little "leaky" at 140 psi.. however, the Zeagle ZX is a balanced 2nd stage, and a few psi above spec (135 psi for the Flathead 6) should make no difference...

Probably just 2nd stage tuning.

Good luck, and keep us posted.

Best wishes.

 

[NotSure]

Was your second stage serviced at the same time as your MK17. If so it could be an assembly issue resulting in a enhanced venturi effect.