I have this engine on a log splitter that i bought used. The engine has ran fine for years, until recently. It will start up and run for about two minutes and then starts coughing, spitting, and back firing. It will quit and doesnt want to restart. Once it cools down it will start and same cycle starts. Im thinking its the coil breaking down when it heats up. Trying to find a coil for this thing is a pain in the patoot! The motor identification is FA210D FS00. When i look up the schematics for this engine it calls for a 21171 coil, but then they list several prefixes. Why should it be so hard to find a part for this engine? Help?