A factory splice. The long leg has no resistance in the 10 gauge splice. Then I tested the short leg(previously connected to my glow plugs solenoid), and didn't even find continuity(it was intermittently showing some connection).

Some pulling and the short piece parted right at the splice block. I would guess the wire broke after years of engine vibration(but still delivered enough voltage), as this terminal was on the main starter lug.

Boats are loaded with electrical connectors.