You need to sit on the pegs because the starter wheel extends out of the top of the box. If you don't then the starter wheel hits the chassis and stalls.
I was going to make the box a universal starter by using the L bracket trick to line up the flywheel opening of the chassis on the box so I can start different vehicles but I would either have to raise the lid or cut down the wheel. The other option is to put a layer of plexiglass or something for the chassis to rest on.