High pressure pump issue

It did work for 3 hours?
Old pump on board?

I can put a used one together this evening and ship it out in the morning.

R U sure it isn't a 230V 50Hz motor?
I can't read all the yellow label on the box, but it does show 230VAC at its top.

Anyway, the symptoms you describe indeed suggest a bad running (not starting) capacitor.
Not sure of why there should be 3, though.

Standing by.

I have a new kit to install on the Cat Pump.
Just have not installed it knowing this was a spare pump that was just going to sit.

Did you really trash it?
Or hide it somewhere safe??

You might be unable to spot a defective run capacitor with just a multimeter.
Easier to just replace it and see what happens - it's not a big investment anyway!
If you pull the capacitors out of their brackets and post pics of their labels, we can see who's who.
Don't forget to discharge them, after detaching the wires!

Call the sales guy.
Failure in 3 hours is a warranty issue.
What can they do to keep a customer happy? Find a replacement close by? Help with shipping you another one?

How is your second RO system running?

I hate bugs like this. I can never trust it till I find a problem that I know was the problem.
Intermittent does not fix it self.
Fingers cross for you.

Tell me more about that switch, Like a starter relay on an A/C compressor?
Manual on/off?
Pressure activated?
It is a cap started motor, so I do not think it has a swinging weight switch on the motors shaft,, or does it?

Intermittent does not fix it self. Only luck keeps things going like this.

Like a compressor, a start relay. Just it looks like a cap in that bake-light package.
https://www.witmermotorservice.com/477205015U03-Stearns-SINPAC-Electronic-Switch/item/2VR50-310
Amazon had them.

If the motor starts, don't turn it off.
Ease up on the pressure to reduce noise and ACv current draw, just don't turn it off.

May the Schwartz be with you..

And didn't he mention that a multimeter test with no load on a capacitor is as reliable as tossing a coin?

Based on your latest findings, two things are clear and another remains a question mark:
The two clear things are that the motor is fine, and whenever it doesn't run it's due to a faulty electrical supply.
The question mark is about whether the culprit is the run capacitor or some other parts of the circuit, like the switch you mentioned.
Now, I have no clue about what that switch is for and how it works, but the 40 MDF run capacitor (which I envisaged to be defective already in my post #3) is something I could buy for less than 10 Eur in any electrical store here, so I'd be surprised if you couldn't do the same anywhere in the US.
In other words, it's a no brainer - just replace it and chunk the old one in the garbage. I bet that the problem will not reappear.
Of course, if instead it would, you should look into that switch first, whatever it's meant for.
Hard to comment that without an electrical scheme, though.