To add to that, I like a long zip tie on the sparkplug wire so it can be shut off by some one outside the kart.If its a first time driver a kill switch is alway handy one they can reach .
Brakes are most important . Most take dot5 not dot 3 . So be sure of that before adding or changing . If they work good , leave eM be .
Good clear instructions .
Obviously helmet gloves long pants and shirt . A safe place too drive . Not the street .