Common part available on Amazon , vintage outboard.com, iboats etc… some cheapy “China” impeller cores have been known to “slip” but that was mostly brass cores not plastic… does your cracked core slip if you try to trurn it ??? are you just concerned… or did you have an overheat problem with your 7.5hp ??
Johnson Evinrude outboard impellers, seals, lower unit kits, water pump kits, gaskets – VintageOutboard.com
Chose correct kit year !!! powerhead base gaskets have specific shapes !!! impeller# 18-3001 Sierra
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