Massey Ferguson MF-35 ignition coil diagnostics?

[RichLo]

Replace or test the plug wires while your at it. If one is too high resistance it can burn up ignition components like blue ball syndrome. Gotta get the spark out...

 

[termite]

Alas, got out to the tractor and it fired right off. I'm suspecting it may be a heat soak issue. Will have to chase that down after its gotten hot.