Air conditioning unit problems. Am on the right track to fixing it?

We've been having problems with our Central A/C unit lately. A few weeks ago it stopped working, i tried resetting all the breakers and the unit and turning the whole thing on and off again and it fixed it, a week later, same issue. I had my father come over and take a look, we noted the fan was not spinning at all although we could hear the compressor kicking in. We were able to get the fan running by giving it a little push with a stick as it came on. We thought it could be the capacitor and replaced it, after replacing it, it kicked on the first time with no need from us to push the fan blades so we thought we were in the clear. A few days ago it stops working again, it seems the fan blades are stiffer than they were before. We open it up, spin the blades around a few times, knock on it with a rock to loosen it up (a dad technique) and its working again. For the past two days the unit will work, after a few hours stop, and I have to power off and on the unit again and nudge it with the stick to get it going, it does not stick anymore though.

Me and my Dad think its the motor and we plan to replace it tomorrow, I've read online the new capacitor could be bad too and its still not giving enough juice to start which I feel is unlikely but possible. Is replacing the motor at this point the right direction? Is there any other reason why an AC unit would turn on and then cut off after a few hours, needing a manual jump start to get going?

Appreciate any help, we're located in Florida if its any help and it is HOT!

 

Based on what you've said I'd agree it's the motor. It sounds like the heat is getting to it.
A new motor may require a different capacitor. Some condensor motors require a separate capacitor. Be sure to address that when you get a new motor.