Scubapro G-250 Troubleshooting

[ams511]

Ok so I serviced my G-200Bs and they work well. However, I have a problem child.

I have a g-250 that was free-flowing. I did an underhaul on it by cleaning it and changing out the seat, and replacing the dynamic o-rings on the orifice and the adjuster knob. I also replaced the VIVA o-ring. The o-rings on the poppet look good so I just re-lubed them and reused them.

Now here is the problem. When I reassembled it I cannot get it to stop free-flowing, even if the lever is way low. I get it to a rather soft free-flow and then when I breath it the free-flow increases. However, if I turn in the knob about half-way in I can get it so stop. Being the knob adjusts the spring tension I figure the spring is bad, but I thought they stiffen with age. The IP from the first stage is 140 psi.

What do you guys think? Is my Spidey Sense correct about the spring or can it be something else like the balance chamber? The balance chamber is the older style black version.

 

[johndiver999]

the orifice is messd up?

 

[ams511]

the orifice is messd up?

It looks ok to me. I could not see or feel any defects.

 

[buddhasummer]

I had the same issue once, I replaced the spring and swapped the balance chamber to the new long crown X type and the problem was solved. Unfortunately as I was less than methodical but more akin to a crazed monkey and replaced both at the same time I'm not sure which was the solution, could have been either or both.

 

[buddhasummer]

@couv

 

[rhwestfall]

A little trick in checking parts is to put the poppet and balance chamber together without the spring with it sitting with the seat of a very smooth surface (like glass). If you lightly push the balance chamber down, the trapped air should make it rebound. This will verify seat, poppet, o-rings, lube, and balance chamber health.

 

[rhwestfall]

It may sound silly to ask, but do you have the poppet and lever together correct, not clocked 180 degrees?

 

[rhwestfall]

did you use a jeweler's loupe to check the orifice?

 

[buddhasummer]

did you use a jeweler's loupe to check the orifice?

I bought one after missing nicks using naked eye and finger nail check.

 

[lexvil]

I would suspect, if the poppet is indeed positioned correctly one of three things, orifice, balance chamber or the two tiny o-rings on the poppet.