G14 motor problem?

[oakridge]

I have a yamaha G14 golf cart that I have been working on. The cart sat for a little while and was not used. I brought it home and put 4 gauge wires all the way to the motor, new batteries. This thing acts like it strains at start up on a hill. Kinda sounds like the motor is slipping. If you get the cart in a bind, The motor sounds like there is a slipping on the inside of the casing. If you keep pressing the pedal the motor gets hot along with the wires on the motor all the way to the F/R switch but the battery wires are still cool. Is this a sign that the motor is going bad? On flat ground it runs good. Just screws up on good load or pull. First golf cart I ever got and don't know much about them so it's really throwing me for a loop.