The self closing speed is micro adjustable through the speed screw at the bottom.
Glass door closer adjustment.
Decrease the closing speed.
Increase the closing speed.
If none of these adjustments works then your door closer may be worn out and you will need to buy a new one to replace.
They should be marked on the closer.
Most door closer brackets have slotted holes so you are able to slide them left to right to make adjustments without.
Remove the plate to inspect the door closer body for leaks see below if adjustment holes had not been drill during the original installation measure where the adjustment screws are located.
If your closers are operating either.
Now that you have the cover off you should be able to see the adjustment screws.
Make adjustments to your pneumatic screen door closer storm door closer twice a year when you exchange the screens and glass storm panels.
Replace the plate and if necessary the door and you.
If necessary adjust the pressure control screw on the closer as well.
Adjust swing latch speed.
If you are capable of doing this work yourself.