Impurities in the system will cause repeated clogging of windshield washer nozzles. To flush the system, remove the pick-up tube from the water bag and insert the tube into a pan filled with about 1 qt. of boiling water. Then operate the foot pump as rapidly as possible and expel all the water from the nozzle jets.
Plugged jets usually can be opened up with a small wire or pin. It may be necessary in some cases to clean out the jets by applying air pressure at the end of the tube from the pump to the nozzle before flushing.