Rough inhalation SP balanced/adjustable

[halocline]

I had an interesting experience last week in Mexico during a sidemount cave dive. One of my B/As started to inhale unevenly; there would be an initial sticking, then a rush of air, intermittently. Not every time, and it would frequently start well into the dive. In sidemount you're switching regs frequently, so I really noticed it. It never got bad enough to call the dive.

I was able to figure it out after that day of diving, and got it mostly fixed for the next day. It was not what I expected. (Those are clues) I thought it would be fun to post it here and see if anyone wants to take a whack at diagnosing it. I bet someone will know right away!

 

[rsingler]

During the initial phase when it was "sticking", did you have to suck harder? Or did it breathe easily, but just minimal air flow?

 

[cerich]

Lp seat sticking to oriface, lever issue, possibly a balance chamber issue

 

[Open Ocean Diver]

Lever feet sticking/catching in the barrel?

 

[Couv]

The problem is that the diaphragm is starting to decay and get a little sticky, especially when its a bit dirty and wet. It was probably slightly sticking to the rubber purge cover until enough vacuum pulled it away.

It's either that, or the twit who tuned it last did not go to the AWAP school of regulator maintenance. :-D

 

[rsingler]

Since folks are jumping in, and you say it was "mostly fixed" the next day...
1) since you're @halocline, I'll guess it WASN'T a catching lever. You would have filed the lever square hole on restoring the reg, so
2) a grain of sand stuck between the poppet shaft and balance chamber, as @cerich suggested. It's "mostly fixed" because there's still another tiny grain stuck in the lube that's still catching the oring occasionally.

That's my story, and I'm stickin' to it!

 

[Couv]

Lp seat sticking to oriface, lever issue, possibly a balance chamber issue

Shotgun troubleshooting. Not allowed! (except when actually working on a regulator.)

 

[halocline]

Anyone else?

 

[Couv]

Anyone else?

I guess that means none of us nailed it.

 

[axxel57]

The exhaust valve was not evenly positioned on the spider or slightly damaged, so it took a certain amount of vacuum to close it and initiate the inhale flow.......