I have a pinball game but it's so old I'd have upgrade it from Stencyl 2.2. If I remember right, though, what I did was apply a turning force when the flipper key was pressed, then a force in the opposite direction when the key was released. Just be sure to set the actor origin to the center of the flipper spindle.
On the released event, move the "set flipper up to 'false' " above the "do after". Just like you have done for the pressed event.---How do you handle the event, when user presses the button key, while the flipper is still moving between positions (either up or down)? Do you stop the current movement?Something like, if actor has turning speed, stop it, and then start the new turning.
Better use custom triggered events in general.For key-press/releases, just use them in their own events. Which then trigger custom events.( Like: move paddle up, stop padlle, get paddle current speed, move paddle down )
I made a game with pinball flippers, it uses the joints extension, but can probably be tweaked to work without.