I had a problem with my ag50 not starting on the button but would kick start after a few tries. I could hear the starter clicking when I pressed the ignition button.
I was teaching myself stuff by reading forum posts on this site at the time.
I disconnected the battery, removed the cdi, removed and cleaned the spark plug, pulled a cable off the top of what I believe is the starter and gave the connector a bit of a clean, changed the oil. I then put it all back together and it starts with the button now.
Brads