This applies only to X Series + XStar boats equipped with some type of ballast system. The number of ballast pumps varies from system to system. Authorized MasterCraft Dealers can provide guidance to locate any and all pumps.
Remove two (2) of the cover screws and loosen the third screw. Retain the screws for the reinstallation process. Swing the cover out of the way to allow access to the impeller location.
Using needle-nose pliers, pull the old impeller out of the casing.
Install a new impeller. (It is intentionally larger than the case. While gently squeezing it in, ensure that the paddle wheels angle in the same direction?counterclockwise?all the way around.)
Slide the plate back into place. No silicone is necessary. Due to the built-in gasket, tightening the screws should prevent leakage.