I am working on a TaoTao ATA 125 atv that when the key is turned on the starter will sometimes just start running without pressing the start button. It will do this 6 times out of 10, where the other 4 times it will act normal and I start it with the start button. I am wondering if it is the solenoid going bad or something else.

 

If it only does it when the ignition switch is on, the solenoid is OK. The fault is in the start button or the wiring to it. This needs fixing as the starter will be running along with the engine when the fault is on.

 

it would also be a safe bet that the safety is not working or has been disabled as well