"Come on baby, light my fire...."
[Add your own music - work with me! Work with me! ]
Actually, "Crank" will spool the motor but not provide fuel so it won't light. Three things will happen:
1. The motor will spool a little and sound like a start;
2. The rotors will move a little, giving Chappie a fright; and
3. A small amount of poo will escape the confines of Chappie's internals
[The fourth thing will be major damage to the blades and to Chappie as he falls off, but difficult to see the humour in that part so I ignored it]