Melting ground wire

[Rpeacocok]

I have an 89 mercury mariner 45hp 4 cylinder. I can't figure out why my ground wire coming out harness to engine is heating up to almost melting! Turning engine over for like 4 or 5 seconds I see ther ground wire start smoking. I can't even find the right parts list like carb rebuilds, electric choke and assembly. It has brand new quicksilver remote, new cdi, coils, plugs and wires. Any helpful info would be much appreciated.

 

[Texasmark]

Wires get hot because of excessive current or excessive voltage drop. Excessive current could indicate starter problems, either internal short caused by insulation failure, bad terminations or Bendix/armature lockup due to bearing failure or corrosion. 4-5 seconds isn't very long for a wire the size of battery feed wires to smoke feeding something like 100 amps to your starter under normal conditions.

If the starter is the culprit and your red and black feed wires are in the same environment, then if one is smoking the other one should too. If your problem is cable/contact corrosion and resultant voltage drop, then only one will smoke and the end that has the bad connection is the one smoking. If you 1989 vintage engine installation hasn't been touched in this area and especially if you are in a salty environment, time to undo all the supply connectors and shine up where metal touches metal...internally, and maybe replace the cables as there could be serious corrosion down inside the terminals that are crimped to the feed wires.

 

[faztbullet]

Check the ground strap from starter to crankcase mount