well those symptoms don't suggest a bad mpem or even electrical, Do you know what the compression is? it sounds like it is ethier starving for fuel or plugs fowling, I would try switching it to your reserve tank, the fuel selector switch get mucked up after awhile. If that doesn't work then I would check the sparkplugs and report what color they are , wet, dry, black.....another possiblilty is you have oil in the crank from a leaky seal and fowling your plugs. Keep us posted we will get you back out hopefully lol