Bad Starter or Starter Solenoid?

I've even taken those contacts out, and in a pinch, filed 'em down to remove the burnt pits, and the same on the copper contact washer. Cleaned out and dirt or dust, carefully re-assemble (got to get the phenolic washers and spacers exactly right so as not to cause a short) and good to go. I did this on my denso starter in my Cummins - same design.