Success! The shorting problem was one glow plug
had completely shorted out and the other glow plug would get warm, but not red hot on the tip. The shorted out GP caused the wires in the GP circuit to melt between the preheat button, ignition and amp meter. I also discovered, thanks to Mainesail, the wiring
harness "trailer connector" had melted slightly next to the positive and alternator/amp meter wires. Not sure what failed first. There were no fuses
in the positive wire going to the panel, despite the wiring
diagrahm showing fuses
Using advice gathered here and from the Newport
owners sites. I ran a new ground wire, amp meter wire and positive wire around the harness and installed new ignition switch and new glow plug switch & wiring as well as new wiring behind the panel.
And the damn glow plug wire still got scalding hot, the top of the glow plugs were hot and still no start. Finally decided to pull the glow plugs and used an ohm meter to test + a manual test and they were bad. My best guess is that there was enough resistance causing the bad glow plugs to get hot externally, that it fooled me into thinking they were working, so I concentrated on finding a short and rewiring. Installed new ones and it fired up immediately.
I plan to use Mainesail's advice and get rid of the amp meter circuit and install a volt meter, eliminating the long wiring run. Additionally, I'll add a solenoid or relay in the glow plug circuit and get rid of another long run high amp circuit.
And yes, I did add a fuse in the postive line that runs to the pane, , next to the starter soleniod and I am researching fusing at the batteries.
Thanks again for all the great advice. This forum is a wonderful resource.