How to restore a Scubapro Mark VII Honker

[Couv]

I knew there was a reason I steered clear of dentists, lol!

What the difference between a dentist and a sadist?
A sadist has newer magazines. :-D

 

[James79]

What the difference between a dentist and a sadist?
A sadist has newer magazines. :-D

And the masochist visits both?

 

[Perryed]

Just so you all know, I`m NOT a dentist! I made crowns & and bridges for them to order. Now a little S&M...………………………………………….

 

[Bryan@Vintage Double Hose]

I've asked @rsingler to collaborate with me on bringing some new ideas he has had success with for putting the honk back into the honkers.

 

[Perryed]

I've never considered sanding the outside of an o-ring; but it's not unheard of-and sometimes encouraged to sand the inside of a seal to remove the "flash." Flash is the tiny bit of material left over from the manufacturing process. Removing it is sometimes necessary especially on cheaper o-rings. Don't tell anyone-as some might think I'm obsessed, but I always ensure the flash is removed from piston stem o-rings. @Perryed I have a variety of -117 seals I'll be happy to send you-PM me your snail mail address and I'll get them out to you.

I received the O-rings from couv and have tried them in my restored MK7. I only was able to test them at 120 psi so they may be different at higher pressure, but at that pressure, none of them would honk. The blue one that couv sent seemed to maybe just get a little vibration going. I did sand down the outer edge of one of the others until it slipped into the chamber fairly easy and it would then honk. It seems that they were both too stiff and ever so slightly too big. I will retest them when I have access to a tank and can try them at 500psi and below.

 

[Couv]

I only was able to test them at 120 psi so they may be different at higher pressure, but at that pressure, none of them would honk.

If they don't honk at 120psi, then higher pressure is not the answer. I would try @rsingler 's o-ring sanding trick next.

 

[Perryed]

Yes, like I stated, that does the trick. As long as the oscillator o-ring Is sanded down far enough for it to slide into the honking chamber easily they`ll honk. If you can pull the oscillator out with your fingers with just a little resistance it`s all good.

 

[Couv]

The blue one that couv sent seemed to maybe just get a little vibration going.

If I remember correctly, that was the softest (by feel) of the bunch. I think it was also the only used seal I sent.

 

[rsingler]

I'm sittin' here on a bag of 50, from my experiments. Anyone wants a couple of the EPDM 2-117's, just shoot me a P.M.

And any of the others, for that matter. They make great Mk10 turret orings!

 

[kelemvor]

I've got a working honker. My LDS (Sunshine Scuba in Largo, FL USA) serviced it a year or two ago. It took him a little while to get the necessary parts but he got it done. Mine does have an adapter on it so I can have two second stages and a SPG. Unfortunately mine has the "low pressure" yoke on it. If it had a regular 3000psi yoke it would be usable for regular diving, it breathes just fine. I actually like the "honker" feature. A nice backup low gas notification with no drawbacks that I'm aware of. Pity that my MK25's don't honk.