[Milsurplus] PE-73 Dyno starting solenoid running hot

[Laura and Jim]

I had my BC-375 up and running for about 45 minutes yesterday trying to check into the west coast MRCG net and noticed "a hot smell" toward the end. I shut down and found the starting relay on the PE-73 too hot to touch. Really stunk up the shack when I pulled the cover. Everything else on the dyno was normal, temperature-wise (warm, but not HOT). Never sounded funny. Bearings seem OK. DC from the PSU is clean when I scope it. I measure 28VDC at the input for the solenoid itself, 28 across the main power lugs on the business end. "ON" switch on the 375 did not feel unusually warm.

Is this normal? Should I be shutting down between transmissions? Couldn't find any trouble-shooting or resistance/voltage references in my copy of the famous 1943 manual, so I don't have a base line to compare against.

I want to blame it on a partially shorted starting solenoid winding drawing too much current, and/or cruddy contacts. 
Or is it just a loose nut behind the mic again...........?

73 DE JIM K6FWT