Brew a pitcher of coffee and then pour some out into a white bowl or coffee cup. If you see small particles of coffee grinds floating in the liquid, you are using the wrong type of coffee. Only use coffee grinds specified for percolators, since percolators have larger basket holes that finer grinds can slip through.
Disassemble the percolator and examine the metal parts for a white buildup, which is calcium and occurs in areas with hard water. If calcium builds up on the appliance, remove it by placing 6 cups of water in the tank and 2 tbsp. of cream of tarter in the basket. Run the percolator through a cycle and rinse it out.
Alter the water temperature if the coffee flavor is too weak. Only fill percolators with cold water that is between 40 and 50 degrees Fahrenheit. Warmer water creates a weaker flavor.
Reduce the amount of water you add if the percolator overflows while running. To identify the proper amount of water, open the percolator and remove the basket. Look inside the tank for a maximum fill line printed on the rear vertical tube. Do not exceed this amount of water.
Check the electrical cord if the percolator does not begin brewing within five to 10 seconds of turning it on. Push the base of the cord into the base of the tank firmly with your fingers and ensure the plug end is securely inside the electrical outlet. If the percolator still does not turn on, the electrical components are bad.
Unclog the percolator tube if the unit turns on but does not brew coffee. Shut off the device and remove the lid and basket. Insert a narrow brush or knife into the tube all the way to the bottom to dislodge the clog. Prevent clogs by covering the tube with your hand while inserting coffee grinds.