Question - I screwed up and reversed battery cables

[Big Frog]

I have a 1993 48 HP Evinrude, and I accidentally reversed battery cables. Well I know, I shouldn't have. But I wasn't paying attention and I did.

And it burned out something in the engine. I took off the hood, and smoke was coming up from the rear of the motor.

I assume I burned out the rectifier and the power pack. Is there anything else I should order that might have burned out too?

I'd like to go ahead and order anything I'd need instead of having to reorder later.

Thanks for any opinions.

John

 

[tashasdaddy]

Re: Question - I screwed up and reversed battery cables

see if the engine will start. you definately toasted the rectifier.

 

[Vic.S]

Re: Question - I screwed up and reversed battery cables

Rectifier without doubt. Hopefully thats all.

 

[Big Frog]

Re: Question - I screwed up and reversed battery cables

OK, I'll give that a try. I'll order a rectifier and see if it starts.

Edited: Should I try and see if it starts before I get the rectifier? will that hurt anything more?

Thanks again,

John

 

[wilde1j]

Re: Question - I screwed up and reversed battery cables

A fried rectifier won't prevent starting, only charging.

 

[Big Frog]

Re: Question - I screwed up and reversed battery cables

Thanks for the replies.

I got the motor started. (it had been in storage for a long time). I think I drained the carburetors but I'm not positive.

It will start up, but die after a few seconds of running.

Is that likely because the carburetors need cleaning, or could it be that I have also toasted something else in the circuitry?

Thanks

John

 

[ezeke]

Re: Question - I screwed up and reversed battery cables

Map the rectifier wires ang disconnect them. Bad advice on starting - if the rectifier wires fuse inside the potting, battery voltage can reach the stator and destroy it.

The rectifier is not necessary to run the motor.

 

[Big Frog]

Re: Question - I screwed up and reversed battery cables

Thanks. Would there be a problem if I disconnected all of the wires to the rectifier and started it? Or should I wait until I received a new rectifier?

 

[countvlad]

Re: Question - I screwed up and reversed battery cables

Thanks. Would there be a problem if I disconnected all of the wires to the rectifier and started it? Or should I wait until I received a new rectifier?

yeah i wouldnt way until gets there.. unless you have a short memory
but once you disconnect the rectifer dont start the motor... let it sit


disconnect the battery.... then start disconnecting the rectifier and mark every wire, and whatever you disconnect .. make sure when you get the new rectf you know where everything goes....

 

[Big Frog]

Re: Question - I screwed up and reversed battery cables

OK, I'll wait until I get a new one. Should I go ahead and order a stator? Whats the odds that I zapped it when i started the motor while ago?

I'm still wondering about the power pack. In that the motor did start, does that mean the power pack is OK, or could it still be zapped from me reversing the battery cables earlier?

Thanks,

John

 

[wilde1j]

Re: Question - I screwed up and reversed battery cables

If the powerpack were fried, it's unlikely you could get it to start at all. BTW, I've run several motors for weeks with a bad rectifier, with no ill effects. Ezeke may have encountered otherwise. With the rectifier still connected, if you can get it to run long enough, check the AC voltage across the yellow pair to tthe rectifier. If you get => 30 VAC at fast idle, the stator (as far as charging goes), is fine.

 

[Big Frog]

Re: Question - I screwed up and reversed battery cables

OK, Kewl. I'm going to order a new rectifier and a shop manual. I'll try to not do anything stupid again to screw it up even worse.

 

[Big Frog]

Re: Question - I screwed up and reversed battery cables

I found a factory OEM service manual for Johnson Evinrude 25 40 45 48 50 55 HP Shop Manual 1992 on ebay. So I bought it.

I ordered a Sierra rectifier from iboats. The picture of the CDI brand shows a plug that you plug into another cable. I don't know if those pictures are just generic pictures or not, But I ordered the Sierra because it displayed a picture of the wires with screw eyelets like mine.

Is one brand better than the other?

 

[ezeke]

Re: Question - I screwed up and reversed battery cables

If the powerpack were fried, it's unlikely you could get it to start at all. BTW, I've run several motors for weeks with a bad rectifier, with no ill effects. Ezeke may have encountered otherwise. With the rectifier still connected, if you can get it to run long enough, check the AC voltage across the yellow pair to tthe rectifier. If you get => 30 VAC at fast idle, the stator (as far as charging goes), is fine.

We have numerous reports of damage to stators and some fires when failed rectifiers' wiring fused, no reference on powerpacks that I am familiar with, though.

As a matter of troubleshooting ignition problems, disconnecting the rectifier is usually listed as one of the first steps in most manuals.

OMC Service Bulletin (see SB 1370) recommendations on rectifier problems go back as far as the mid 1970's.

Not to belabor the issue, but what possible harm could come from running the motor without a rectifier? You won't answer that because there is no rational answer.