bad solenoid?

[Sandman]

I have a question relating to a G9 gas Yamaha, just the other day the starter decided to engage all by itself. The key can be turned off at the starter will start to spin without any warning. The solenoid will click but even if the gas pedal is pushed and then released it will not stop. I have disconnected the battery and checked the ground (even added an additional ground) thinking the other might be weak and no change. I am new to golf cart ownership and do not know a lot about them. Even after I am able to disengage the starter (I dont know what helps) it will after minutes start all by itself.....