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 you'll know that it matches your pump exactly. 40mm 1.57 . Width 19mm 0.57 . Impeller article number 09-808B-1. MC97 for cooling . Replaces Jabsco 22405-0001 Europe USA. Inner diameter 12 mm The impeller is a very important security device. Its task is to pump the water through the cooling Width 19mm 0.57 . Impeller article number 09-808B-1 MC97 for cooling . Replaces Jabsco 22405-0001 Europe USA Inner diameter 12 mm