Modifying a Scubapro Pilot Aspirator?

[redacted]

I have an upgraded pilot (coaxial valve) and it is giving me some freeflow problems. It breaths great (maybe too good) but I have to be very careful handling it on the surface as it is prone to freeflow and does not stop easily. Sometimes covering the mouthpiece does not do it. It requires the tank be shut down. I suspect the freeflow is so strong that it may be inverting the diaphragm. I have pretty good luck controlling it with the dive/pre-dive switch by keeping it set to pre-dive unless I am submerged. The other day my buddy had problems with his double hose reg leaking so we went to the surface where he could shut it down and tighten it (might have been better to handle UW). In any event, I hit the surface without switching to predive and spit out my reg (bad move) and it went into a violent FF. Covering mouthpiece did not work, nor did covering mouthpiece and the exhaust ports. We tried to cycle the tank valve and that significantly reduced the FF but the reg continued to leak a bit every time the valve was opened. So I shut it down and and went to shore and swapped out the 2nds stage for a D-300. Troubleshooting the problem later, I found that the diaphragm had had partially come out of the backup disc (nut in middle of diaphragm). I suspect my attempt to block the mouthpiece and both exhaust ports push the diaphragm out so violently as to dislodge this connection. It did not come completely loose but just enough to not allow the lever to return and allow a seal.

So, has anyone modified the original non-adjustable aspirator to restrict air flow. Mine actually looks like it was opened up at bit from stock just make more air flow. Will a D-series aspirator fit on the pilot. I have not put them side by side but except for two sets of legs connecting to the inlet vs one, that looks like a good solution if I can find a spare D-series aspirator.

 

[DA Aquamaster]

With the Pilot and Air 1 diaphragm, the distance between lever and diaphragm is controlled by the turing the little rounded hex shaped knob on the outside of the diaphragm.

I have not observed the proilem you had on a Pilot, Air 1 or Pilot to Air 1 upgrade, so I suspect something is amiss with the adjustment of the reg.

 

[redacted]

If I understand this correctly, it sounds like I should disengage the lever from the rod and then set cracking pressure by adjusting the spring pad. Finally, I should adjust the rod in the backup disk so that it engages the lever without causing flow.

 

[halocline]

With the Pilot and Air 1 diaphragm, the distance between lever and diaphragm is controlled by the turing the little rounded hex shaped knob on the outside of the diaphragm.

So it is...I'm looking at an air 1 diaphragm as I write. The eye for the lever is on a long threaded plastic stud, you could adjust it out more than 1/4" if necessary. Mine gets loose pretty quickly, but I guess the lever would keep it from moving.

Unfortunately, this same diaphragm appeared to have a pin hole near the edge, and when I gently stretched it near a light, guess what happened.....I wonder if I can fix it?

If anyone, ahem, has an air 1 diaphragm for sale, I'd be very interested!

 

[redacted]

So it is...I'm looking at an air 1 diaphragm as I write. The eye for the lever is on a long threaded plastic stud, you could adjust it out more than 1/4" if necessary. Mine gets loose pretty quickly, but I guess the lever would keep it from moving.

Unfortunately, this same diaphragm appeared to have a pin hole near the edge, and when I gently stretched it near a light, guess what happened.....I wonder if I can fix it?

If anyone, ahem, has an air 1 diaphragm for sale, I'd be very interested!

If the hole is close enough to the edge (outside the sealing rim), you might be able to position it under one of the flats on the clip where it should have no effect. But it still might only last another 25 years.

 

[halocline]

So, has anyone modified the original non-adjustable aspirator to restrict air flow. Mine actually looks like it was opened up at bit from stock just make more air flow. Will a D-series aspirator fit on the pilot. I have not put them side by side but except for two sets of legs connecting to the inlet vs one, that looks like a good solution if I can find a spare D-series aspirator.

I'm not sure what adjustment you're talking about, is it the venturi assist adjustment tab on the D series that you want to put on the pilot?

 

[halocline]

If the hole is close enough to the edge (outside the sealing rim), you might be able to position it under one of the flats on the clip where it should have no effect. But it still might only last another 25 years.

It's now torn. I'll bring it next time, you might have an idea. Maybe some sort of silicone cement. The tear is right where the edge meets the thin body of the diaphragm, and it looks like that edge is the sealing point.

 

[DA Aquamaster]

Those diaphragms are very hard to find. I have a couple of spares but I am selfishly hording them as I am probably going to use Air 1's for sidemount stages.

 

[halocline]

Those diaphragms are very hard to find. I have a couple of spares but I am selfishly hording them as I am probably going to use Air 1's for sidemount stages.

Would you mind leaving them to me in your will?

Just kidding....

 

[Texfrazer]

The tear is right where the edge meets the thin body of the diaphragm, and it looks like that edge is the sealing point.

Hey Matt,

You might want to try a good electrical rubber splicing tape. If the tear is right at the edge of the sealing point, you might have to cut the tape to form a sealing edge around the top and bottom of the diaphram, with additional material along the top and bottom of the tear (if this makes sense).

By the way, I'm not saying this is easy or it will work, but I might try it if it were my diaphram.