Kymco not starting by takes a jump

[bknewyork]

My Kymco 150 will not start on its own.
When I attach a jump start battery it starts right up.
I've also tested the battery, which is fine.

When I remove the jump start battery and try to start up again i get nothing.

Is it the starter or the solenoid?

Any help would be hugely appreciated.

Thanks
Berl