Hot Earth fault

[Simon B]

Here's a strange one; Yamaha 100 4 stroke 2004 engine

Was powering up our electrics on saturday after some rewire work. Tested out the loom and found a blown fuse, replaced it, yes I should have looked for the fault but didnt at that point.

There is what looks like an original Yamaha in line fuse holders on red and yellow, the red (previously blown) circuit wasnt infinite resistance about 15K Ohms. After about 15 minutes of power on an earth bonding wire started smoking, not red hot though and didnt blow 10 amp fuse, our steering is also bonded to negative as well at present. Killed the power and removed the fuse. This circuit appears to power a gauge speed/trim. Havent tried starting the engine yet so dont know if it will start and run with or with out blowing the red wire fues.

My only firm guess at what happened is that somehow the main -ve wasnt connected and it

[Simon B]

Does anyone know whether, when you reconnect a battery from an engine that has been downpowered for some weeks, is there an initial surge of power to stuff like the capacitors etc in the CDI system (dont even know if our has them am presuming it does) That may account for a heating effect on the bonding strap if battery -ve lead isnt connected correctly?