To elaborate for you, beej67, I don't understand why it didn't heat up at the dock. I can only think of two reasons: 1. obstruction or 2. it wasn't loaded up as much as I thought it was. (No tach to verify.) Both have already been mentioned here.
The thorough cleaning is an attempt to get the boat back up to shape. I bought it used recently and it has sat for 4+ years. It was an accomplishment just breaking it loose and sailing.
I'm interested in that flush that Freesail mentioned. I've heard of Barnacle Buster and Salt Away but haven't heard if either work any better or worse than a weak acid solution.
Also (maybe this needs to be another post) there is no raw water screen between the thru hull and raw water impeller. Shouldn't there be one to catch debris coming in? Thanks for all the help!