I'm in favor with Marc's (Frenchelectrician) post.
3 Capacitors would (normally) indicate a Capacitor Start / Capacitor Run type
This Motor could very well be intended to be run at 230 VAC 1Ã˜ (but not absolutely!).
Two Capacitors would be in the Start circuit (for a very large starting value), and the third one (also in the aux. circuit)
would be the "Run" Capacitor. The Run Cap would be much smaller than the Start Caps.
Several reasons for the stalling include:
[*] Frozen / sticky Bearings on the Motor, the Pump, or both,
[*] Extremely high head pressure,
[*] Incorrect operating Voltage,
[*] Voltage too low,
[*] Genny cannot produce enough locked rotor power,
[*] Failed Start Capacitor(s) - shorted or open,
[*] Centrifugal Start Switch is not closed for Start,
[*] Centrifugal Start Switch is not opening after Starting Sequence has taken place.
An extremely apparent, but maybe overlooked item may be a Polyphase Motor???
Capacitors would be there only for P.F. correction... sounds very unlikely to me... but....
Chances are the problem is a result of sticky bearings, or something similar, which would keep the pump / Motor from rotating freely.
Check the obvious first, then move up towards internal or system troubleshooting.
Start with the simplest stuff first.
If the problem(s) turn out to be internal, check the Capacitors. If you need help on Cap tests, let us know.