recommended electronics for a razor go kart
 

A buddy gave me an electric razor go kart a while back, piddled with it some today. The batteries are shot for sure, don't know about the esc, but kinda kicking around going brushless. I will take some pictures of how it is set up this evening. I was thinking a 100a or so plane esc, 6s, and some sort of outrunner, servo controller. I have a bunch of rhino 4900's in 2s and 3s, so would like to do something I could use those with. I hooked a jump box up straight to the motor thats on it, it actually pulled me around the driveway better than I figured just on 12v, I think the kart was originally 24v. I am not looking for a speed demon, maybe 12-15mph, basically just to ride around the driveway while my son is on the power wheels he is getting for Christmas, maybe 30 minutes or so run time. I have scanned through some of the e-bike builds, and am continuing to do so. I have quite a few brushless, 1/8 scalers, but not really messed with outrunners, or a project like this. Any help is appreciated.

I would say to definitely get an outrunner. The lower total rpm means less gearing down is necessary, and if you get something like this, you'll definitely have power if you decide to go faster down the road. For the ESC, I'd take a look at an CC HV ICE ESC. You can run ~6s for now, and then 10-12s in the future.