7xl hot need better set-up?

Yeah, the guy at StarluckRC, said (and I hope that I don't misquote him) that motors really have a sweet spot, in terms of current draw, that they like to run in. He said that a motor will run hot due to either overgearing or undergearing. It sounds like you're undergeared. Go ahead and try gearing up. If it makes the truck too fast for your application, you'll probably have to try a higher turn motor, which may not be a bad thing. It'll be easier on the drive train and you should get more runtime.s