Peugeot Vivacity 50 problems - help needed!!?

my Peugeot Vivacity 50 broke down around a week ago and when it broke down the engine and the fuel seemed pretty hot, i waited for while for the engine to cool down and it did start again but went off. it now wont start at all. the spark plug wasnt sparking so we thought that what it was, so we bought a new HT lead and it is now sparking but the moped still wont start. any help would be brill thanks