Blowing rectifier

[LaveyT]

A buddy has a 1989 150 Mercury. It has the 40 amp system on it. Neither one of us is much of an electrician but we tested the stator and it checked good if we were reading it properly.
We have hooked up a 6 wire 20 amp rectifier/regulator. They seem to do fine on multiple trips until reving over 4000 rpm then they pop.
the original had a purple wire as well but nothing like that on the 20amp jobs.
We are not sure if running 2 20 amp regulators would help ?
Any thoughts on what may be going on appreciated.
thank you!

[PanRonnie]

It would help

[LaveyT]

Thank you,
I think there are only two yellow wires coming off of the stator. I’m not sure if two regulators can be run off of two yellow wires.

[rprinzo]

Thank you,
I think there are only two yellow wires coming off of the stator. I’m not sure if two regulators can be run off of two yellow wires.

gotta be 4

[RoyE]

If you only have two yellow wires coming off the stator, that stator was meant to be connected to the old 40A water cooled regulator/rectifier.
The output on those two wires is up to 40A. No wonder your 20A rectifier/regulator pops over 4000 RPM.
I don't think you can run two regulators off the two yellow wires. You either need to change your stator to the 4-wire one or run a 40A regulator/rectifier.

[LaveyT]

If you only have two yellow wires coming off the stator, that stator was meant to be connected to the old 40A water cooled regulator/rectifier.
The output on those two wires is up to 40A. No wonder your 20A rectifier/regulator pops over 4000 RPM.
I don't think you can run two regulators off the two yellow wires. You either need to change your stator to the 4-wire one or run a 40A regulator/rectifier.

Thank you,
that’s what we needed to know.

[rgsauger]

Without doubt, the best plan is to swap to the system that has four yellow wires. I ran dual 20 amp regulator rectifiers in parallel on my 40 amp flywheel for a couple of years and it worked just fine. Cannot say it is the best thing to do but it did work for me. I have since swapped to a 16 amp system which has only one 20 rec/reg but dual in parallel did work for a couple of years.

[LaveyT]

Without doubt, the best plan is to swap to the system that has four yellow wires. I ran dual 20 amp regulator rectifiers in parallel on my 40 amp flywheel for a couple of years and it worked just fine. Cannot say it is the best thing to do but it did work for me. I have since swapped to a 16 amp system which has only one 20 rec/reg but dual in parallel did work for a couple of years.

So , did you run two 20 amp regulators on a 40 amp stator/flywheel with two wires? If so how did you wire it?

[rgsauger]

Sorry it took so long for me to get back. I can take a picture tomorrow of my rig and show you what I did basically I just wired two of them in parallel which means hooked up the wires for both of them just like you would for one of them. I figured that each of them would end up sharing the load to some degree. It did work for a while. Never failed, I just changed to a 16 setup. Not something that I can formally recommend but it worked in my case. Somebody else posted a better aftermarket voltage regulator on one of the posts not too long ago. You might start another thread and ask about alternative regulator rectifier’s.

[LaveyT]

Sorry it took so long for me to get back. I can take a picture tomorrow of my rig and show you what I did basically I just wired two of them in parallel which means hooked up the wires for both of them just like you would for one of them. I figured that each of them would end up sharing the load to some degree. It did work for a while. Never failed, I just changed to a 16 setup. Not something that I can formally recommend but it worked in my case. Somebody else posted a better aftermarket voltage regulator on one of the posts not too long ago. You might start another thread and ask about alternative regulator rectifier’s.

Thank you,
the 20 amp regulators are only about $20
the 40 amp is about $500 to $700 depending upon ho you purchase it from

[rgsauger]

Exactly! I think mine were $25 or $30 each. Used the gray wire (tach) on just one of them. Tach worked fine. Like I say, someone else posted another option that might be better not long ago. You might start another thread here in Technical.

I don't run heavy electronics or heavy electrical load in my boat. If you don't need the higher output, you can always swap down to a 16 amp setup, too.

Keep digging on that other rec/reg. There was a link in here not long ago.

[Darkcloud]

Hey guys. I have a 1985 150 merc. Motor wasn’t charging. Changed rectifier and tested at home on ear muffs got 13.6v. I was a happy camper……until the following day when I took her out for a test run. At start up motor was charging at approximately 13.6v. Once I got the revs up about 3500rpm voltage jumped to 17v. In a panic I shut the boat down went through the start up sequence again and motor did exactly same thing. I went back to Mercury dealer (who won’t warrant electrical components) and questioned them on why this was happening and they seem to think it’s rectifier. I have never heard of regulator until now. It’s possible this is the problem
Id like to check this out can you guys help. Where is the regulator
Pete.

[rgsauger]

It sounds like you need to add a regulator also. The rectifier is obviously working because it is converting AC voltage to DC voltage. It is not however regulating the voltage. In the USA, we can get them for 25 or $30 on Amazon or eBay. Sounds like you need to add the regulator combination, not just a rectifier.

[Darkcloud]

It sounds like you need to add a regulator also. The rectifier is obviously working because it is converting AC voltage to DC voltage. It is not however regulating the voltage. In the USA, we can get them for 25 or $30 on Amazon or eBay. Sounds like you need to add the regulator combination, not just a rectifier.

Thanks
How do I know what type of amp output my motor is?

Pete