cdc is right could be a faulty starter but check the easy things first. you will have a thick wire from the battery 12v and a small wire from the ignition switch or button, 12v when you turn the key or press the button. you need a test light or multimeter to test it. if you have 12v at this wire check the earth wire to the engine if this is ok starter is no good.
Raz
March 2016