Sta-Rite pool pump hums but will not start; motor housing gets warm and trips the breaker or thermal overload.

Safety: Turn off the breaker and verify no power is present. Capacitors can hold a charge; discharge them safely before handling.

• Check for free rotation: Remove the Sta-Rite pump lid and basket. Reach the impeller or use the rear shaft end (under the fan cover) to see if the shaft spins freely. If it is stuck, inspect for debris or bearing failure.
• Inspect the capacitor: Remove the motor end cover to access the start capacitor. Look for bulging, leaking, or burned terminals. Replace with an identical microfarad (µF) and voltage rating capacitor approved for Sta-Rite pumps.
• Examine start switch/relay: On some motors, a centrifugal switch or potential relay engages the start winding. Check for broken springs, burned contacts, or stuck mechanisms. Replace the switch/relay if defective.
• Test run: After replacing the capacitor or switch and ensuring the shaft spins freely, restore power and briefly start the pump. If it still only hums, the motor windings may be damaged and the motor should be replaced.