Switched Positive & Negative Battery Leads

[raglrv98]

I have a 1989 Mercury 80 HP ELPTO Outboard motor and have an electrical question. It has come to my attention that the positive and negative leads, from the battery, may have been switched, accidentally. The starter was engaged a couple of times during this polarity switch but the engine would not start (not surprising to me) Anyway, I was wondering if anything in the electrical system would have gotten fried because of the switched polarity (i.e. sensors, switch box, trigger, stator, solenoid, low oil module, etc.). I am not sure what to check and how to check some of the electrical modules for correct operation. I sure don't want to go into next spring with dead modules and sensors.<br />Thanks for any help.

 

[GregC]

Re: Switched Positive & Negative Battery Leads

All the ignition components should be fine (I would think as they are connected to the battery.) I would test to see if you fried the recitifier.<br /><br />-andy

 

[dakk1]

Re: Switched Positive & Negative Battery Leads

Yep, bet that rectifier is fried.<br /><br />Dave..

 

[molsenice]

Re: Switched Positive & Negative Battery Leads

Michigan Boating, as personal experiance has shown me, GragC, is incorect. Sorry to be the bearer of bad news, but this error is going to cost you not only a rectifier, but a swichbox as well. However, noting that you have an '89, mabey it is I who am incorrect as you may not have a switchbox, yours being more modern than my '67. Check with your local marina and do a search (above) on the topic and read through them as you are not alone in what has happened to you.

 

[Motor Boater Bill]

Re: Switched Positive & Negative Battery Leads

Does it start? Will it start if the battery is charged? What's it doing?

 

[molsenice]

Re: Switched Positive & Negative Battery Leads

Listen to Motor Boater Bill - this guy is my HERO!!!

 

[raglrv98]

Re: Switched Positive & Negative Battery Leads

The engine was working fine for about 6 hours over a few weeks. Then, I believe it overheated and it just died. Now, the crank will only move about 3/4 of a turn and hits a hard stop. OH &*%^$#. I had someone look at it and he said it is major. He used to build engines from scratch and he and I talked for a number of hours. I am in the process of disassembling the powerhead to see if I can rebuild it. I am planning to replace the mechanical parts as necessary, but am unsure what may need to be replaced electrically. I do have a switchbox, for reference.<br /><br />Your help is greatly appreciated. You are all a blessing for your time and replies.

 

[timmathis]

Re: Switched Positive & Negative Battery Leads

You will have to cross that road when you get there. (If you know what I mean) If and when you get it fixed.(The powerhead)you will have to troubleshoot your ignition if you have an issue with it. It would be hard to guess what damage if any it did when you crossed the battery wires. Hope this helps, Tim

 

[molsenice]

Re: Switched Positive & Negative Battery Leads

Michigan Boating - wow how did you go from crossed battery terminals to an overheated rebuild? - that kind of info would be handy to know right from the get go. Check to see if the starter hasn't fully disengaged - as for your electrical woes, remember - give the folks here ALL the info on the engine - otherwise it leads to misdiagnosis and wasted time. - rectifier and switchbox are toasted if the terminals were even touched w reversed polarity, arched, or disconected while the motor running. Also, checking for spark with an spark plug not grounded will damage elect components(directly from the Mercury Service manuel)good luck hopefully it isn't the dreaded muffler bearings, they' really tough to find.

 

[ronmold]

Re: Switched Positive & Negative Battery Leads

I use Amsoil and have NEVER had a muffler bearing failure!

 

[Motor Boater Bill]

Re: Switched Positive & Negative Battery Leads

I'm with Tim Mathis on this--you've got major bit of mechanical work to do before you get to the electrical, and it may involve evaluating whether the powerhead can be repaired or needs to be replaced. Or maybe you'll get real lucky and the powerhead will be a relatively straightforward fix. Either way, you need to get that squared away to see how your electrical parts are behaving, then everyone here will no doubt be glad to help with troubleshooting the electrical system--but it's hard to check for spark when the crank won't turn!<br /><br />Good luck!

 

[molsenice]

Re: Switched Positive & Negative Battery Leads

If it turns out to be a muffler bearring, good luck finding a good Sky Hook to remove it.