2005 115hp electrical Issue!!help!!

snowy23

Cadet
Joined
Mar 30, 2006
Messages
17
Hello all. Been a while since I last visted but I'm back for a friend in need.
The skinny:
Motor is 2005 elpto 115hp - SN 1b157946
control box id - RC881170A15 - sn-28 11/29/04.

2005 115hp merc on mid 80's bayliner. All was fine before last weekend. We took batteries out for charging (2 Batteries). When replacing batteries, my partner shorted a neg post with his wedding ring (got a nasty shock). Tried to start and nothing had power. Finally figured the neg cable from engine was connected to pos terminal on main battery. Corrected that and she tried to start. The starting is very hard and sporadic. Sounds like a weak battery but when it finally starts it runs well and will start often. The bad part is we fried a wire from control box going to tach when we connected the batteries with the battery switch in the off position and key was also off. The control box has been rewired with the small black plug going nowhere and three wires going to tach, purple, black and gray. The black wire keeps melting when we connect the battery cables with all power set to off.

Reading elsewhere I understand the purple is +12v, gray is sender, black is ground. We think somehow the battery switch is bad and are going to disconnect it alltogether to check. Other than that we are confused. What is causing the black wire to burn when all systems seem to be off?
Any help would be appreciated.
Many thanks in advance.
 

SBTOM

Petty Officer 1st Class
Joined
Jul 22, 2009
Messages
275
Re: 2005 115hp electrical Issue!!help!!

This sounds really similar to a problem that I am having with my 1997.... the black ground wire going into the ignition keeps getting fried! Did you ever figure out what the problem was?
 

jacobsonsr

Recruit
Joined
Jul 21, 2009
Messages
1
Re: 2005 115hp electrical Issue!!help!!

The problem we had was we had the ground wire connected to the positive terminal of the battery. What a stupid mistake.
 
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