Sounds like you have a dead cylinder, check and make sure all plug wires are on. Check the plugs see if you have a wet one then you can find which cylinder it is, and go from there.
I just checked the timing also. It seems to be all out of whack.
I just had a carb shop tune this thing just over a week ago. They set the advance at 18 initial and the total was capped at 36 with an FBO plate.
At 750 rpm I'm at 10 advance
At 2200 I'm reading 50 advance.
