Rojo, you sent me this in a PM: "Powerhead bolts on a Yamaha they are the worst. I use Kroil and if I can get it to move a little go very slowly working it a little then let it cool. Yamaha bolts are terrible for wringing off."
Now I'm worried about attacking those bolts. They are next on my agenda. The one thing maybe I have going for me is the fact that since the engine was redone 8 months ago with a new (used head), new (used block) and a new oil pump, maybe they'll be easy enough since they were recently removed and had spent less time in the salt. And supposedly, it was not run for four of those months. So, only occasional salty fishing on the weekends for four total months. He said it ran great during that time.
And I think I was able to clean up the bottom of that lower piston with scotch-brite. dono. feels smoother, looks pretty much the same.