Wow! I have been following your post hoping the next thing you try get's it started. May-be that 360 would be the best bet. I'm like you, I hate to give up.
With all the checks and adjustments you've made it should start and run. Who knows, maybe the prev. owner picked up a cam at a swap meet and it was a marine cam that runs backward. Good luck! It sounds like you've covered all bases. toolmanmike
