Also if the fuse holder turns out to be the problem - don’t replace it - toss it in the trash it really does nothing. If you want to have a fuse move it to the power (red) coming off the starter lug going up to your panel. 15-20A would be good.
Les
The OEM fuse is problematic, but there should be a fuse there. If the solenoid goes bad and you have a locked condition, it's like a locked rotor on a pump. It will fry the wiring all the way back to the "B" terminal of the starter solenoid. In other words, a complete round trip. There are accounts and pix on the net of the outcome of that happening and it isn't pretty. To avoid issues there, prepare a pigtail with an uninsulated female quick connect on a 10 awg weathertight AGC fuse holder, and a watertight quick connect on the other end. Carefully solder the uninsulated quick connect to the solenoid "S" terminal so it never comes loose and falls off, heat shrink over it all. Then the other end w/ the weathertight quick connect to your harness "S" wire can be used for troubleshooting, or to remote start the solenoid if needed.
Take a 10 awg AGC weathertight fuse holder, crimp a #8 x M8 LUG (NOT ring terminal) on one end, butt crimp on the other end. (Fold the bare 10 awg in half and it's perfect diameter for a #8 LUG.) Put in on the "B" terminal, and crimp the butt end to your red power wire to the panel.
NOW you have an ABYC=compliant harness that is NO LONGER a fire hazard because it's unfused.