It is very likely the start capacitor, or start windings. (If it's the windings it's pretty much shot.) If the motor has been running hot the windings could be going bad, if not it is most likely the capacitor. It is possible that the bearings, or something clogged in the impeller could be affecting it but not likely. (just something to keep in mind). The capacitor is fairly easy to test if you have an analog meter, and easy to replace as well. Without knowing the exact motor model. I can't give exact directions. Before I give you more details, you may want to just take the motor down to a pump repair shop they should test it for free. If you want to tackle it yourself, then continue on. You may have start, and or run capacitors. The capacitor(s) is either under the big metal hump protruding from the side of the motor, or in the tail end with the wiring. (or both) Either way it looks like a black or silver canister. At this point you should obviously have removed power to the motor. If you remove or check the capacitor remove the wires carefully and discharge the capacitor by shorting the two leads. To check the capacitor you need a special capacitance meter or an analog ohm meter. Some capacitor testers give a reading, some just an audible tone. To check with a meter it has to be an analog meter. Set the reading for ohms, and set for the lowest setting, maybe 1 ohm, or 10 ohms. When you connect across the terminals you should see the needle flick upwards then slowly drop. This is only a generic reading but gives you an indication the the capacitor is functioning. If the needle doesn't move, then it's probably open (bad) or if the needle moves all the way up and stays, then it's bad (shorted out) if you get a reading needle flicks and drops, you'll need to short the leads to test again. Replacing the start cap is cheap ($10-$20) compared to a new motor. You can usually find a replacement cap at Grainger, a pool pump repair shop, or sometimes at a local pool supply retailer. Hope this helps. If you need further assistance post a reply in the comments, and don't hesitate to leave a good thumb rating if you found this helpful. Thanks, and good Luck!