The only way to adjust the timing is to move the key on the crank, so if the crank and/or flywheel has worn down the key then the timing will be off.
The spark you showed in the video was a nice strong spark, I see no reason way it won't run.
Turn off the fuel and try starting to get rid of the rich condition, leave the fuel off and put a small amount of fuel in the throat of the carb and try to start it that way. If you get it to pop off a couple times, then you know the timing is good and the issue is fuel relat