Control box troubles

[empty shell]

My control box button doesnt lock to stop from going in reverse. Its locks and has to be pushed it to go from neutral to forward, but when going to forward to neutral it doesnt lick back from stopping it from going straight into reverse. Any idea what may be broken? Took box apart and didnt notice anything broken.
Also motor stalls when going from reverse to neutral sometimes and doesnt seem to be going over 3800 rpm. Could this have something to fo with the control box problem also?

[boats.net]

Remove handle and check lock plate.