Pond Boss Forums AERATION Systems questions Problem with Gast pump

Finding this thread on a google search, I have the same Gast 1/3hp pump (model 75R) as Freedomeagle and now having the same problem.

The motor won't start, it just hums.

I just rebuilt the pump several weeks ago with new cylinders, cups, gaskets, etc., and it was running like new. Then Monday morning went out to the pond to find the pump only humming, and warm. And this was after 4" of rain in 2 hours along with high winds Sunday night yet the inside of the cabinet was dry).

The fan blades spin freely so it's leading me to the capacitor. But not having a capacitance tester, I only have a digital and analog mulitmeter.

The rating on the capacitor is 10uf, 440VAC

On the digital one set to Ohms I get no reaction (although on the tester it shows the Ohm symbol to 250V, my capacitor shows 440VAC), it just stays on "OL". On the analog tester set to "Ohm X1k" (only setting), when I touch the contacts the dial jumps to 3 then drops back to zero very quickly. When I reverse the contacts it does the same thing. If I touch the contacts a second time, there's no reaction, only each time they're reversed.

Does anyone know of another or better way of testing the capacitor, short of finding someone with a capacitance tester?

Thanks!

Keith