why did this burn?

[longshanks]

1998 Mercury 2-stroke 60HP triple. Has been used for years with no issue. The other day, about 5 minutes after shutting down, I noticed smoke coming out of the cowl. I disconnected the battery cables and let'r smoke... Boat wouldn't start up and I had to get towed out...

I took the cowl off later, to discover that the wiring harness which connects the tiller-mounted ignition/key to the starter has a black (ground) wire that completely melted, causing all the smoke. I have a new wiring harness on order, but I'm asking myself what would have caused this thing to burn up in the first place?

Any ideas?

 

[SBTOM]

Re: why did this burn?

Just out of curiosity, did you ever figure out what caused this? I've had what sounds like a similar problem with 100hp 1997....

 

[j_martin]

Re: why did this burn?

If your main ground cable is loose or defective, then starter current (or trim current) will try to flow through the signal ground. It will smoke.

hope it helps
John

 

[verado7]

Re: why did this burn?

sounds like a live wire touched ground somewhere . not good but it happens

 

[longshanks]

Re: why did this burn?

posting back for the benefit of others.

the reason it burned up was that I had a quick-connect set up for my battery cables. The ground connection eventually wore out, and caused the ground wire in my wiring harness to short out and make a hell of a mess. I replaced the wiring harness, and improved my quick-connects, hopefully preventing this from happening again. lesson learned.

thanks for your help

 

[verado7]

Re: why did this burn?

ahh quick connects - i saw them at the parts store - and left them there - batt cables need to be tight and stay that way . with convenience comes a price .