I've finished constructing the fuel system, and apparently managed to get all the plumbing right, including a dump valve at the fuel tank. But I don't think the fuel automatic is working right. It has never been used since it was overhauled, so I don't have any history on it. But here is how it acts.

1. Back off the adjusting screw until it is finger-loose.
2. Put air in the pressure tank. It all blows through, back into the fuel tank. I can easily hear the bubbles.
3. Slowly tighten the adjusting screw, 1 hole at a time.
4. Put air in the pressure tank each time. It all blows through, but a bit more slowly with each hole I tighten the adjusting screw. Presumably I'm moving the needle closer and closer to the seat.
5. Eventually it's to the point where no more bubbles can be heard in the fuel tank.
6. Put 120 psi air in the pressure tank.
7. Pump fuel with hand pump. Pressure rises to 160.
8. Loosen the adjusting screw - 1 hole, 2 holes, 3 holes. No pressure decrease.
11. Loosen the adjusting screw, 1 hole. No pressure decrease. Beginning to hear noise in the fuel tank.
12. Hand pump fuel, pressure rises to 165 psi. Hearing slight noise in fuel tank.
13. Loosen the adjusting screw, 1/2 hole. A bit more noise in fuel tank.
14. Loosen the adjusting screw, 1/4 hole. The valve pops open and dumps all pressure back to the fuel tank, down to 0 psi.
15. The adjusting screw is now finger-loose.

It seems like I'm moving the needle in and out with the adjusting screw, but there is simply no diaphragm-spring behavior at all. Does this make any sense? I don't think it will serve its purpose while driving, will it?

You say it was overhauled, what was changed?
It sounds like the spring is two stiff. Most spring operated pressure regulators have a dead band between when there closed and opened.
How does it work in a higher pressure range. Say 150-to 200 on the air tank.

Rolly

Hi Kelly,
Have you accidently connected the fuel auto round the wrong way, the pressure side is at right angles to the unit the tank connection is at the bottom, in line with the unit, it sounds like you are adjusting the unit until the valve is hard on the seat, and as you back off the needle will pop off the seat, the fuel comes in on the back of the needle and under the diaphram forcing the diaphram against the spring pressure, hope this makes sense, all the best, Jeff

Jeff,,,Good thinking,,I think you have it,,Cheers,,Ben

Argh, I had a faint suspicion about this but did not follow up on it before writing. That was exactly the problem. Reversing the connections caused the automatic to function as expected. It now bypasses smoothly at 135 psi & recloses fine.

But the beautiful component layout, and the lovely carefully-bent tubes... I guess that'll be enough crowing about how clever I've been.

Thank you, gentlemen.

Kelly

Kelly don’t feel bad the 1908 Stanley instruction book page 20 has the piping diagram of the pressure regulator wrong.

As a side note my regulator has 20 PSI dead band. I have it set for 120 PSI. When it opens to by pass fuel it does not set (close) till it reaches 100 PSI This is tested with air back feeding through a bucket of water. I’m not sure what it does with the seats are wet with fuel. The bypass is very small at 110 but still leaking some.

Rolly