Modern Vespa

2018 MP3 500:
I'm having an issue with an MP3 that has sat a while. Got it running but the throttle won't turn more than an 1/8 turn. Seat sensor seems to work. The light goes out when I sit on the seat. The throttle turns enough to turn off the wheel lock but the rpm's stop at 3K. If I get off the seat, the throttle won't move at all. Ideas?

Corroded throttle cable. This is usually at the throttle grip end on the bars. Only sensible cure if this is the case is to replace both cables.

So dismantle and inspect!

I thought that originally but I've taken the cables off the throttle body and the grip turns fine. Something is telling the throttle body to limit the travel.