Not sure what engine you have but it has points and I found 3 different ways to set the timing in a manual
1 - point gap
2 - test light, more accurate, static.
3 - timing light, lining up the marks dynamically.
It also appears that the points are camshaft driven, it the cam/crank is off 1 tooth the engine would probably run but would not run right and the ignition timing would be off for sure.
I think the motor is not making the power it should from what I see in the video.
I triple checked myself when I lined up the crank and cam gears.
The only thing i did in regards to the timing was adjusted the points. I can see about using my meter to check it better.