Take good care of the cooling system - change to a new impeller every year the impeller is a very important security device. Its task is to pump the water through the cooling system of the engine. But remember that the impeller should be replaced every year. And always make sure you get a johnson pump brand original impeller. Then youll know it matches your pump exactly. 65mm width 50, 2 mm impeller article number 09-1028b neoprene for cooling replaces jabsco 17937-0001 europe and usa.