Johnson Pump MC97 F6 Threaded ImpellerMC97 F6 Threaded Impeller Replacement A worn or damaged impeller can cause system failure or engine breakdown. SPX's Johnson Pump brand impellers are developed and manufactured for maximum flow and long life. With a genuine spare impeller, you can also be sure that you are getting the quality required by engine manufacturers and professionals. Features: Designed to fit Johnson Impeller Pump F6 Specifications: Material: MC97 Pump: F6 Outer Diameter: 2.