My dad retired after years in the army and after doing electronics - he checked all the electrickery for me and said it all seems ok there.
Yep, my first step is to pull the rear plugs and have a look. Then I will take the huge intake off the top and see what is underneath and what I can see from there. Rocker covers and sump will happen after that, and if I still haven't found the problem.......
There are motors available, but not cheap ($1600 at a first look) but it is also not worth just getting a new motor without looking first. Costs me nothing but time to pull it apart. Not sure I can get it back together by myself but it is not working now, so I don't have much to lose....