Ive been sitting back watching this thread, and it appears as if you want a magic answer. There is no such thing. You've been asked to verify timing with a light, but you haven't. You are assuming your timing/electrics are ok.......but they may not be. You've been asked to pressure test your engine, but you haven't. I had an engine fresh from the machine shop leaking......they can and will leak. You don't mention condition of coil........could need replacing. Wires break down fairly often in those. What is the compression and the squish of your motor? What condition are the reeds in?
Unfortunately you need to test and diagnose all these things. You can't assume parts are good and things aren't leaking. There is only one way to do it and that's the right way. If you don't have the equipment, take it to someone who does, or keep chasing it like you've been doing. It may be worth setting up an appointment with someone that knows what's up, even if it means driving a few hours.
Good luck getting it fixed!