My name is Peter. I am a retired field service refrigeration technician.
You did not provide a model number which is located on a label on the liner side wall of your refrigerator section, so I do not know what ice maker you have.
Most ice makers do not have a water fill adjustment. If you have a square box cover on the front, then you may have adjustment. On the right hand side there may be a tiny plastic stem with a slot for knife or tiny flat head screw driver. Turn only 1/2 clockwise. Or with difficulty pop off the front cover and you will see an adjustment spring for water fill.
But, I do not think this is your problem.
1.) Your water fill tube my be iced up inside. Using a small screw driver break the ice up in the fill tube.
2.) If this does not solve your problem, then you probable have a bad ice maker solenoid, where either the coil is weak or the spool sticks and does not open all of the way for the fill cycle.
This is easily replaced. It is probably a duel valve assembly where you have to replace the whole assembly.
a.) Locate your model number.
b.) Go into the below website, put in your model number, you will get parts diagrams prices and part numbers.
c.) Go into the internet and search the part number for the valve. You may be able to find a used valve for conservable saving.
d.) Up plug the unit. Turn off the water supply valve.
e.) Remove the back bottom cover.
f.) Disconnect the valve assembly retaining screws that hold the valve assembly to the unit.
g.) Remove the electrical connectors on the valve assembly.
DO NOT GET THEM WET.
h.) Remove the main water supply line to the valve assembly. There will be water in this line.
i.) Remove the plastic tubing to each valve. Push down while holding the small retaining locking ring. When reassembling, push the plastic tubing down, not hold the retaining ring. You should hear a click meaning it is locked in.
Water Filters Lawn Garden Appliance Parts