On the weekend I replaced my Sherwood impellor for the first time....hopefully the last time! I re-read this thread after the change out and now understand the frustration of others. There are just too many awkward things that need to happen to replace this part. How do you ensure that the O-ring is seated when you carefully slide the outer housing onto the shaft? My boat will be launched this week and I can only hope that I have assembled this properly and that it is leak free. In an emergency situation there is no way that the impellor could be changed in a timely manner. Like others on this thread, my next change out will be a change over to the Oberdorfer, and I am thankful for all the info above.
Cheers
Cheers