I have been fighting with an older Stihl 031AV. It will start and run to WO and then die. I have been through the fuel system and now I am on to the ignition. (150 lbs of compression, by the way) I cleaned and reset the points and the old Bosch WSR6F plug will show a bright yellow spark for 1 or two pulls and then drop to a vey weak and tiny blue spark. I have done the searchs on this and have seen the suggestions for the Atom module etc. Do you guys think the plug maybe just bad? I have no replacement tonight to test with. Do I need to split the fuel tank to remove flywheel? It looks like I am not going to get away without buying the work manual for this saw.