Feeder always tilt down

If the feeder cover is loose (can't stop in the middle) always tilt down, i have the solutions:

1 Go find piece of acrylic about 3 mm thick
2 With a screwdriver hold the spring and slide it the acrylic at the left side (see pict)
carefull the spring is hard and difficult

If you done the feeder is now can stop at the middle not going down or close all the time