Moped Army

After starting the moped I give it gas, and the moter just revs, and the bike dose not move. I have to pedal the moped pull the start lever, and give it gas still pulling the start lever untill the, I am going to say the second speed clutch engages but it mite be the first speed clutch. I dont think the moped shifts after the clutch engages. Also after I come to a stop the clutch wont engage. What is the problem, and how to fix it.