Johnson Pump Impellers Used by Original Equipment Manufacturers for Over 50 Years With The Strict Tolerances that Deliver Maximum Performance in Engine Cooling.. Stable pressure delivering correct cooling at startup and continued running. MC97 rubber compound minimizes swelling with less failures due to fatigue. Exact OEM required dimensions resulting in less blade wear & better engine cooling. Broadest offering in the marine market space. (Not one size fits many approach). Kitting provides everything needed to complete the entire process