FX Any Repair places in Oregon or Washington?

it is between the bottle and the first regulator
Then one of the seals on the reg adjuster is bad, it's a 10 min fix. If it's leaking of the top it's the top o-ring.

The schematic sent has different hardness's i.e. NBR90 instead of NBR70, this makes sense except one is several mm thicker than possible in its location. The on-line schematic has the old durometer numbers but the right sizes. Numbers below correspond to the online schematic, with the right hardness, besure to lube them with something slippery

13) 10.0 x 1.5 NBR90 inside Regulator hole at bottom of threads
18) 7.5 x 2 NBR70 Regulator Body
20) 4.0 x 1.5 NBR90 End of Piston
23) 4.0 x 1.5 NBR90 Inside Regulator Body
25) 2.0 x 1.0 NBR90 (2x)

On the adjustment screw hold it reverse in the adjuster housing in a soft clamp then slowly stretch the #25 on, then the second one, be prepared to break a few.