Will a 1/3 horse power sump pump motor burn up at half power?

[Weird Al/ Tony]

alright thanks. ya see I'm trying to get a powerful motor that will be hard to stop while it is receiving power. that way it will be able to power my robot through all opposition. (this robot is for like a hobby, not the competitions) and I'm thinking that I have some older wheelchair motors, and other stuff. but they arent very fast and they dont have much power. I'd probably need either a gear box or some good belts to allow diffrent speed and torgue. I kinda think I know what i'm talking about. I mean I'm just getting on a team so I dont have alot of robotics experience.