Not a hard job
Lets assume you have a Yanmar since you didn't say. But it should be similar on any type. Make sure you have the proper parts INCLUDING a new gasket. Close your raw water input seacock. Remove the hoses and belt from the raw water pump and remove the pump from the engine. Were talking about two hoses and two bolds. It's easier to work on this way. 1. Remove the 6 screws holding the plate on the back of the pump. 2. Remove the plate. You need to pry it off the housing. 3. Notice the orientation of the vanes on the impeller. (Left or Right). 4. Pull the impeller out with pliers. It may be tight. 5. Clean/scrape off ALL of the old gasket until the surface is smooth. 6. Replace the impeller with the vanes oriented in the same position as before. Hint: Lubricate the whole impeller with liquid laundry detergent to make it easier to replace into the housing. 7. Ensure the impeller in flush with the surface of the housing. 8. Replace the gasket. 9. Replace the plate. 10. Replace the screws. 11. Remount the pump on the engine. Attach hoses & belt. 12. OPEN THE SEACOCK. 13. Start the engine. Give it a few seconds to start pumping. When it does, you'll see the suds coming out and you are in business. 14. Save the old impeller as a backup and have a few extra gaskets around also. 15. Go sailing. Good Luck!
