If you know how to do so, check the voltage while the pump is running.

OR, engage the multimeter with the pump OFF, and then have someone turn it ON while you are watching the voltage. It shouldn't drop more than 3% -- 4 volts at 120; 7 volts at 240.

It's harder to check for a short across the windings; you can check resistance, but unless you know the 'good' value, it may not tell you much.

Do you have an ammeter? (Amp-meter)

. . . I'm going to ask Mark to take a look; he understands electric motors better than I.