Rectifier Replacement

Big Claude

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Sep 10, 2013
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I have a 1992 Johnson Faststrike 150 with a bad rectifier/voltage regulator. The manual is not clear on the removal of the retifier and I would like to know what is involved in replacing it. Is there a gasket or an o-ring underneath the unit? I know its water cooled but most replacement units do not offer the rectifier with a gasket so I am in question about its removal. Is there anything I need to look for to insure it is getting properly cooled? The wiring looks pretty simple, just unplug old and plug in new. I imagine the battery needs disconnecting before starting. Any help will be appreciated.
 

F_R

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Jul 7, 2006
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Re: Rectifier Replacement

Original part number is replaced by 0439561. Includes a gasket.
 

Chris1956

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Mar 25, 2004
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27,034
Re: Rectifier Replacement

Wait until you see the price......I bought a CDI replacement. That one rusted thru, if you can believe it.
 

Big Claude

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Re: Rectifier Replacement


Thanks for the help. I was pretty sure there was a gasket there but wanted to hear from someone that knows. I know its water cooled is there anything I need to look for to make sure its getting cooled properly. Had no other problems with the motor and it seems to be cooling properly. I just recently purchased the boat and the previous owner had a water pump installed last yr and also the compression checked. Thanks again!
 

Big Claude

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Sep 10, 2013
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Re: Rectifier Replacement

Tell me about it. I imagine it has all of $10.00 worth of electronics in it but they know its a must have. I am wondering what caused it to go bad, age probably. Did you have to do muct prying to get the old one off?
 

Roberthill

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Dec 3, 2012
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317
Re: Rectifier Replacement

Should not be that hard to change .Rectifer has diodes in it , changing current ac to dc(or is it dc to ac) has to have problems after a while .
 

Chris1956

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Mar 25, 2004
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27,034
Re: Rectifier Replacement

Well, the VR is a bit more complicated than a simple bridge rectifier. It should taper the charge as the battery voltage rises. This tapering will be tied but not controlled by engine RPM. i.e. if the battery is fully charged, and the engine is running at a cruise speed, the charging rate should be small. if the battery is discharged, the charging rate should be higher, possibly limited by the engine RPM.
 

dingbat

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Nov 20, 2001
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15,414
Re: Rectifier Replacement

Did you have to do muct prying to get the old one off?
I replaced mine in the dark when it was 25 degrees out. Had a fishing trip the next morning. Shed some blood, but it's came out reasonably easy. The worst part is removing the power pack so you can get to it.

A loose battery connection will burn a rectifier. Make sure you battery connections are tight, replace wing nuts with ny-loc nuts if you have not already done that. ;)
 
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Chris1956

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Mar 25, 2004
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27,034
Re: Rectifier Replacement

Ding, His VR is located behind the flywheel, under a plastic cover. 4 bolts, two amphenol connectors and a ring connector on the starter solenoid battery post, plus a ground. Not hard in the light. The powerpack is below it and can stay installed.

But I like your attitude.....
 

Big Claude

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Sep 10, 2013
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Re: Rectifier Replacement

You are right, I checked to see where it was located before I posted. The power pack doesn't have to be removed on my model and the VR should be no problem to take off. It's like anything mechanical, if you haven't done it before it pays to ask someone who has. I didn't know how hard it was going to be to pry it off and also didn't know what to look for to make sure its being properly cooled. When you're spending well over $200.00 for a part' especially an electric one, you want to get your ducks in a row to keep from shorting it out or doing more damage than you started with!
 

Chris1956

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Re: Rectifier Replacement

Claude, Make sure to count the number of cables on the battery stud on the starter solenoid, as you remove them. Put back just as many. And do not forget the ground wire. It should ground under one of the bolt heads. You may need to advance the throttle to get to one of the bolts. I put some permetex #3 on the gasket, since I reused mine.
 

Fed

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Apr 1, 2010
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2,457
Re: Rectifier Replacement

I think the only trap in this would be not re-installing the flywheel by the book.
 

Big Claude

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Sep 10, 2013
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Re: Rectifier Replacement

Thanks for that tip and I will be sure to do this. I did notice that the throttle must be advanced to get to this bolt. I removed the cover when I suspected the rectifier was bad just to see what it looked like and also to see if I thought it was a job I could tackle. Thanks again!
 

Chris1956

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Mar 25, 2004
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27,034
Re: Rectifier Replacement

Fed, The flywheel is not removed for this repair.
 
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