pump cycling, no water output
My 1 hp irrigation pump was cycling on what looked like low pressure (about 30 pounds) with breaker at pump sparking. I replaced burnt out brker. Pressure immediately came up to appx 50 pounds. I ran all cycles w/no problems. Days later, with cycles off and pump plugged in, pump was cycling again, pressure low and breaker sparking. I unplugged it. No leaks found in yard. Pump and motor is approx 3.5 yrs old.
Suggestions what to do next to pinpoint problem? hellp