The pump on the old BMW was facing forward, it took about 47 seconds to get the screws out, plate off and new impeller and gasket changed out. The Yanmar pump plate is facing aft and is at the bottom so you need to either pull the entire pump off to do the work, do it be feel from the back of the pump or I suppose use a mirror to see what you are doing?

Pulling the pump means pulling the drive belt as well, so removing and putting this all back together is about a 30-45 minute job......at the dock.