HELP!!! Battery switch shorted out and made negative positive and positive negative!!

[moondog419]

I don't know how but i just replaced my 88 115hp merc with a 2002 merc 125hp and when I hooked up the cables + to solenoid and - to starter housing all of a sudden a lower ground wire glows red and burns through ARGH!! I put a tester on it and the - became positive and + became -. so I pulled out the battery switch and connected positive directly to battery and now its correct, but what could be damaged?! Please tell me if you have heard of this before.

Thanks Dylan

 

[snodgrass.zach]

Re: HELP!!! Battery switch shorted out and made negative positive and positive negati

I don't know how but i just replaced my 88 115hp merc with a 2002 merc 125hp and when I hooked up the cables + to solenoid and - to starter housing all of a sudden a lower ground wire glows red and burns through ARGH!! I put a tester on it and the - became positive and + became -. so I pulled out the battery switch and connected positive directly to battery and now its correct, but what could be damaged?! Please tell me if you have heard of this before.

Thanks Dylan

ive done that before!!!!!!!!! fix the wire that toasted and check all ur other ground to make sure they arnt toasted to and hook the battery up right and turn it over to see what happens.....i had nothing else wrong with mine after i did that

 

[emckelvy]

Re: HELP!!! Battery switch shorted out and made negative positive and positive negati

If it still runs after you correct the polarity problems, use your voltmeter to check DC output. Measure at the battery terminals or at the "hot" wire on the starter solenoid. You should get a rising DC voltage as you raise the fast idle lever to, say, a max of 1500 rpm. Don't ever run the motor faster in Neutral on a flusher, it's bad for the innards to run without a load.

If the DC voltage doesn't rise with rpm, or actually drops, the regulator/rectifier assy is fried and needs replaced. You can look up parts here at www.iboats.com

If you can't find the part here, try www.boatfix.com

Check this site for parts diagrams (you'll need to know your Serial #):

http://www.mercruiserparts.com/SelectModelType3.asp?class_id=2

Replacement of the reg/rect assy is pretty straightforward, disconnect battery, disconnect wires from reg/rect, unbolt the bad unit and install the new. You may need some heat sink paste (what's used for computer CPU's is great or get some from Radio Shack) for the new unit.

Hopefully the rectifier/reg isn't fried, cross your fingers!

HTH........ed

 

[moondog419]

Re: HELP!!! Battery switch shorted out and made negative positive and positive negati

Thanks for the help guys apparently the problem was a weak ground so(I still don't fully understand, how) the motor or the battery was searching for a ground and in the process melted the ground wire on the transom at least this is how the boat shop explained it. Thanks again Dylan

 

[j_martin]

Re: HELP!!! Battery switch shorted out and made negative positive and positive negati

Thanks for the help guys apparently the problem was a weak ground so(I still don't fully understand, how) the motor or the battery was searching for a ground and in the process melted the ground wire on the transom at least this is how the boat shop explained it. Thanks again Dylan

If the main engine ground isn't connected, and there's a path through small diameter (instrument) wiring, it'll smoke as soon as there's a starter current or trim current draw on it.

Usually just hurts the wire.