OMC Rectifier - hooked batt up backwards

BillP

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OOPS, another senior moment...I hooked up my batt on the wrong terminals and pulled it back off. Full juice got to the engine for a few seconds. Can't detect a problem and the motor runs fine. Did the rectifier or anything else get damaged? Engine is a 91 omc 65hp johnson commercial (same as the 70hp 3 cyl domestic).<br /><br />Thanks for your input and advice.<br /><br />Bill
 

Silvertip

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Re: OMC Rectifier - hooked batt up backwards

If you have a voltmeter, check the battery voltage before you start the engine. Then start the engine and check voltage again. If the second reading is higher than the first, the rectifier is ok and the system is charging. If you have a tachometer and it's working, thats a sign the rectifier is ok as well.
 

BoatBuoy

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Re: OMC Rectifier - hooked batt up backwards

I don't mean to pull you down, but usually just a bump of reversed polarity will fry the rectifief, lest it did mine. Upinsmoke's advice is good and will tell you definitely. Let us know.
 

BillP

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Re: OMC Rectifier - hooked batt up backwards

Thanks for the info. I've read it fries rectifiers but need to find out if it did. The tach was broken before hooking up so I can't benchmark with it. I'll check the volts soon as it stops raining.<br /><br />Bill
 

Stumpknocker

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Re: OMC Rectifier - hooked batt up backwards

It can fry it, but it doesn't always do so. I have hooked up a battery backwards while swapping out a dead battery in rough winds once and it wasn't caught for a few seconds. 90 Evinrude survived. I was sure it whacked the electronics, but I dodged the bullet. Even tried to crank the motor while it was backwards. Its definately a bad thing however.
 

BillP

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Re: OMC Rectifier - hooked batt up backwards

Gil009,<br />That's encouraging!<br />bp
 

Scaaty

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Re: OMC Rectifier - hooked batt up backwards

Just as a reminder..."couple seconds" is meaningless. Electricity is NOW. Older motors would fry stuff (why do I know this?), but newer have chip technology to isolate us that do dumb stuff. Do the voltage meter test and you will know. Good Luck....and get out that red spray paint or use nail polish on the + terminal!
 

BillP

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Re: OMC Rectifier - hooked batt up backwards

I checked the batt and no voltage increase. The rectifier must be fried. It started raining so I didn't get to check the charging system to make sure a charge is getting to the rectifier. Lucky for me this motor has the pre 92 rectifier...$40 instead of $175.<br /><br />Robby...I'm red and green color blind...thought the green was red and poof. I usually ID the posts but didn't this time. <br /><br />Thanks for the help guys.<br /><br />Bill
 

ob

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Aug 16, 2002
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Re: OMC Rectifier - hooked batt up backwards

Bill,did you run the engine up to around 2500 rpm to see if the voltage increased across the battery or just run it at idle speed? Makes a difference.What type of meter are you using?digital ?analog?You'll only get a 1 volt or so increase if the charging system is putting out and that will vary slightly depending on the battery state of charge.Probably did fry the rec. but just to be sure.
 

BillP

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Re: OMC Rectifier - hooked batt up backwards

Originally posted by ob:<br /> Bill,did you run the engine up to around 2500 rpm to see if the voltage increased across the battery or just run it at idle speed? Makes a difference.What type of meter are you using?digital ?analog?You'll only get a 1 volt or so increase if the charging system is putting out and that will vary slightly depending on the battery state of charge.Probably did fry the rec. but just to be sure.
ob,<br />I checked it at a fast idle but nothing near 2500. I will try it at higher rpms tomorrow. It's an old analog meter. I noticed the needle was bouncing just a tad. <br /><br />I believe the rectifier is a 3-10 amp. The number stamped on the rectifier is 511938 and I can't find that number listed anywhere. Parts lists show a 3 wire with PN 583408 or 1533408 for the motor. Is there a cross ref for the stamped number?<br /><br />Thanks,<br />Bill
 

Joe Reeves

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Feb 24, 2002
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Re: OMC Rectifier - hooked batt up backwards

Bill.... Assuming that you do indeed have the small 3 wire type rectifier which has one RED wire and two YELLOW wires, you can test it as follows and eliminate the gures work.<br /><br />(Small Rectifier Test)<br />(J. Reeves)<br /><br />Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction. <br /><br />Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other. <br /><br />Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires. <br /><br />Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.
 

BillP

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Re: OMC Rectifier - hooked batt up backwards

Thanks for the excellent response everyone. I also checked rectifier as Joe described. It was definitely fried. I bought a new OEM rectifier for $42 locally (ebay had a one for $15 but I didn't want to wait) and it's on the motor now. Final checks show the new rectifier is working.<br /><br />In case anyone wants to know. The number stamped on the part is not the OMC/Bomb part number. Old and new still have the same stamping and part numbers.<br /><br />Bill
 

stage1ny

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Apr 2, 2012
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Re: OMC Rectifier - hooked batt up backwards

I had to replace my rectifier after battery was hooked backwards.
Can this also hurt stator?
I seem to also have no output on one of my 2 power packs.
1987 Evinrude E110MLCUR.
I tested output while cranking engine of both power packs.
Found almost nothing on one and almost 5v on the other.
Just want to know before I order new power packs as I would swap out both.
Thanks.
 

Joe Reeves

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Re: OMC Rectifier - hooked batt up backwards

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