What is enough fuel pressure?

[PGBuick]

Running a '48 59AB in my 36. Have a fairly new mechanical fuel pump (not sure where made, but it appears to be a good quality pump). I have a formed hard line between the pump and Stromberg carb and a fuel pressure gauge t'd off it. Seems it used to run 2-3 psi last fall, but now is down to 1 psi and the gauge flutters a lot. Seems to run fine until it's warmed up, then it's either flooding or starving and runs poorly. I have an inline electric pump to push potential vapor lock through, but never needed it.
What should the fuel pressure be with liquid fuel coming from the mechanical pump? Is the gauge fluttering a symptom of pump diaphragm failure, or maybe something else?
Thanks all.

[ford38v8]

You won't get a steady pressure reading on a gauge between pump and carburetor, as the carburetor's needle valve will open and shut as required. An accurate reading can be had by capping the Tee and supplying the carb with an independent source. Pressure specified is 3-4 lbs, but should be fine with as little as 1½ lbs. Higher pressures tend to open the needle valve too much.
On a side note, save the old pump springs for possible use in new pumps, as some new springs are stronger than spec.

[69a]

Flooding could only be caused by the needle and seat in the carb.
Low pressure on the outlet of the pump can be the diaphragm, either of the one-way valves in the pump, or a restriction between the pump and the tank. Also using a non vented gas cap!
Test the pump by disconnecting the line at the carb. and try to blow the fuel back to the tank with your mouth. (this is close to 3 PSI) any displacement of the fuel means a problem with a pump valve or the diaphragm.

[glennpm]

2-1/2 PSI maximum for Stromberg 97s

[Flathead Fever]

Like Glenn says, 2 1/2 lbs.is the maximum fuel pressure for a Stromberg, any more than that can open the needle and seat and start flooding the engine. Most people are used to 6 lbs. of fuel pressure on a carb but that's too much for a Stromberg.

There are two kinds of electric pumps, ones that when they are off they are closed, fuel can't get through them. The other type when its off remains in the open position so a mechanical pump can still draw fuel through it. In the Airtex catalog (available online) there are just a couple of electric pumps that have the flatheads low pressure rating and remain "open" so you can use it to prime an engine that has been sitting for awhile and then shut it off and run the engine off of the stock pump.

That doesn't answer the question as why you are only seeing 1 lb. of pressure at the carb unless maybe you have the wrong type of electric pump or something is restricting the flow between the stock mechanical pump and the tank. You can try to disconnect the fuel line from the stock pump on the engine and plug it, then hook a gallon of gas up to the fuel pump and see if your pressure increasess at the carb. That way you have eliminated everything from the stock pump on back to the tank. Be really care fuel to have the power disconnected from that electric pump and plug the line before trying this. If the pressure does not come up at the carb, then the problem is probably the original styles pump. Also, the fuel pump's stock riser, where it bolts directly to the intake. Those bases warp a lot and cutdown on the pump rod's travel. I have a mountain of them out in the garage that are warped and junk, probably enough to cutdown on half of the fuel pump rods travel. When you by used ones make sure to check the flatness of them.

[chap52]

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Ran dual 94's on my '52 FH with 2.5 lbs. pressure. Worked great. Chap