Calling all rectifier gurus

I know my rectifier is toast following the tests in my factory service manual. I'm cheap, and don't really want to pay 50 bucks for a new one. Is there any way I can buy a cheap rectifier at a supply house and make it work? I have done a search here and found many options for a three wire but none for a four wire. I understand that my stator puts out three phase. I get about 20 volts between the yellow/blue and the yellow wires. On the yellow/grey tach wire, I can only get a pulse voltage, unreadable with just a dvm. My stator checks out fine according to factory manual ohms wise. I know a four wire has six diodes but is there anyway I can make a simple bridge rectifier work? I don't need the tach wire cause I don't have one.Can I just hook up the two yellow/blue and the yellow wires to the cheap bridge rectifier leaving the yellow/grey open an call it good? Will this make it unregulated and overcharge my battery? Will it damage my stator to not use the yellow/grey wire? Or is there some way to use two cheap rectifiers and make it work? Caution !! I am not an electronics engineer, so please try and keep your answers simple as you can. Thanks in advance.

Re: Calling all rectifier gurus

Simple ansewer, repair your engine properly, cheaper in the long run.
Buy the proper rectifier and install it.

Re: Calling all rectifier gurus

Not a good idea. There's more to it than just "a rectifier is a rectifier". Yes, it could overcharge or undercharge or ???.. If you had the proper equipment to measure the existing one(s), you probably could. But you don't, so don't.

oh ya, and I AM an electronics engineer.

Re: Calling all rectifier gurus

Daviet said:

Simple ansewer, repair your engine properly, cheaper in the long run.
Buy the proper rectifier and install it.

Click to expand...

Well of course that's the easy way out. But I'm always lookin to save some dough. These are tough times, and I don't qualify for a government bailout package.

Re: Calling all rectifier gurus

This will do, but should be mounted on a water jacket surface for cooling...

http://cgi.ebay.ca/1PC-FUJI-6RI100E-080-3-PHASE-BRIDGE-RECTIFIER-/180551968075?pt=LH_DefaultDomain_0

Was the original regulated? I guess I should have asked first....
If it was regulated, putting in just a rectifier will allow it to overcharge.
Its always nice to list your model when asking for help....

Re: Calling all rectifier gurus

Fifty bucks? I laugh, I cry.... The R/R for my 200 cost more than $200! (and I was glad to pay it because the local shop had it the day I needed it!)

Re: Calling all rectifier gurus

if you can't afford a proper repair, you can't afford a boat. buy the dang proper rectifer, or sell the boat.

Re: Calling all rectifier gurus

petryshyn said:

This will do, but should be mounted on a water jacket surface for cooling...

http://cgi.ebay.ca/1PC-FUJI-6RI100E-080-3-PHASE-BRIDGE-RECTIFIER-/180551968075?pt=LH_DefaultDomain_0

Was the original regulated? I guess I should have asked first....
If it was regulated, putting in just a rectifier will allow it to overcharge.
Its always nice to list your model when asking for help....

Click to expand...

Same style as the chrylser rectifier, if it will work why not, i'm all about saving some coin as well, my money tree died a long time ago.

Re: Calling all rectifier gurus

bktheking said:

Same style as the chrylser rectifier, if it will work why not, i'm all about saving some coin as well, my money tree died a long time ago.

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Thanks bk. Looks like that one should work fine. As a side note, just because I didn't want to shell out alot of money for the oem unless I absolutly had to, dosn't mean I can't afford to own a boat as some here have implied. This motor is 30 years old, semiconductor technology has come along ways in 30 years. Who's to say that using this new style isn't alot better then the original? And cheaper too. No money tree here either. Thanks again.

Re: Calling all rectifier gurus

I don't know if this is the same as yours..but its not a bad price....

Al

Re: Calling all rectifier gurus

In case nobody around here knows it, this forum happens to be hosted by iboats. And iboats just happens to sell rectifiers. No need to go off to those other guys, support our host.

http://www.iboats.com/mall/partfind...d_poid=187637&gd_row=130&**********=186332421

Re: Calling all rectifier gurus

Agreed, same price and it supports our provider, just wish they had a Canadian division, if they wanted one I'd quit my job and run the show for them

Re: Calling all rectifier gurus

F_R said:

In case nobody around here knows it, this forum happens to be hosted by iboats. And iboats just happens to sell rectifiers. No need to go off to those other guys, support our host.

http://www.iboats.com/mall/partfind...d_poid=187637&gd_row=130&**********=186332421

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Ya know what f.r. if you would have just told me that I could get this part for half the cost of the brp right off the bat, rather then telling me I should sell my boat because I can't afford it,I would have bought it for 25 bucks. I don't think you understand that I am semi retired, and on a fixed income. 50 bucks is alot of money for me,but I still want to enjoy a little bit of what life I have left. I think that you know in your heart that what you told me was wrong. But I'm gonna suck it up because maybe your old and grumpy sometimes just like me .And forget that you can catch more flys with honey, instead of vinager. But it's too late now because I just got a good used one from a local boat shop for 10 bucks. And it's working...so far. If this one fails, I will buy your 25 dollar one. Peace.

Re: Calling all rectifier gurus

Hi Old Iron

While I do agree that it would be better to fit the correct replacement rectifier, a Sierra one perhaps is cheaper than on OEM one, it is not impossible to make up a suitable rectifier for a small fraction of the cost of a proper part.

If you only had a two wire output from the stator then it would be easy 'cos you could just use a suitably rated full wave bridge rectifier. (Ac to the two Ac connections, Dc negative to ground and positive to the battery)

With the three wire output you are correct that it needs a three phase rectifier containing 6 diodes. ( although it is not strictly correct to say that the stator gives a three phase output)

From an electronics point of you can easily make a suitable rectifier with 6 suitably rated diodes from your favorite electronics component supplier.
They must have a current rating that exceeds the maximum output from your stator and they must have an adequately high peak inverse volts (PIV) rating. I'd guess 50volts would be adequate.

The difficulty might be building a unit in a suitable physical form.

I assume your motor does just have a plain rectifier and not a regulated rectifier. If you substituted a plain rectifier for a rectifier/regulator you would risk overcharging the battery.

Below is a digram that shows, in the top half how the three wire stator output (Yellow, yellow/grey and yellow/blue) can be used to supply AC to lights, and in the bottom half the basic circuit of the rectifier normally fitted.

I you can follow what I have said and can understand the diagram then go for it. If you dont then my advice, I am afraid, is to buy the proper replacement part.


BUT BUT BUT what engine are we talking about. In another thread you mention a 1978 55 hp . that only has a two wire stator out put and a three wire rectifier ... If that the case then back to the beginning ... just get a suitably rated full wave bridge rectifier. Connect yellow and yellow/blue to the AC input connections. Take DC out from the + and - connections

Re: Calling all rectifier gurus

Vic.S said:

Hi Old Iron

While I do agree that it would be better to fit the correct replacement rectifier, a Sierra one perhaps is cheaper than on OEM one, it is not impossible to make up a suitable rectifier for a small fraction of the cost of a proper part.

If you only had a two wire output from the stator then it would be easy 'cos you could just use a suitably rated full wave bridge rectifier. (Ac to the two Ac connections, Dc negative to ground and positive to the battery)

With the three wire output you are correct that it needs a three phase rectifier containing 6 diodes. ( although it is not strictly correct to say that the stator gives a three phase output)

From an electronics point of you can easily make a suitable rectifier with 6 suitably rated diodes from your favorite electronics component supplier.
They must have a current rating that exceeds the maximum output from your stator and they must have an adequately high peak inverse volts (PIV) rating. I'd guess 50volts would be adequate.

The difficulty might be building a unit in a suitable physical form.

I assume your motor does just have a plain rectifier and not a regulated rectifier. If you substituted a plain rectifier for a rectifier/regulator you would risk overcharging the battery.

Below is a digram that shows, in the top half how the three wire stator output (Yellow, yellow/grey and yellow/blue) can be used to supply AC to lights, and in the bottom half the basic circuit of the rectifier normally fitted.

I you can follow what I have said and can understand the diagram then go for it. If you dont then my advice, I am afraid, is to buy the proper replacement part.


BUT BUT BUT what engine are we talking about. In another thread you mention a 1978 55 hp . that only has a two wire stator out put and a three wire rectifier ... If that the case then back to the beginning ... just get a suitably rated full wave bridge rectifier. Connect yellow and yellow/blue to the AC input connections. Take DC out from the + and - connections

Click to expand...

That's a good answer to his question. I shall add, I believe the tach(grey wire) pulse can be read with analog meter set on AC volts in lowest range.

Re: Calling all rectifier gurus

Vic.S said:

Hi Old Iron

While I do agree that it would be better to fit the correct replacement rectifier, a Sierra one perhaps is cheaper than on OEM one, it is not impossible to make up a suitable rectifier for a small fraction of the cost of a proper part.

If you only had a two wire output from the stator then it would be easy 'cos you could just use a suitably rated full wave bridge rectifier. (Ac to the two Ac connections, Dc negative to ground and positive to the battery)

With the three wire output you are correct that it needs a three phase rectifier containing 6 diodes. ( although it is not strictly correct to say that the stator gives a three phase output)

From an electronics point of you can easily make a suitable rectifier with 6 suitably rated diodes from your favorite electronics component supplier.
They must have a current rating that exceeds the maximum output from your stator and they must have an adequately high peak inverse volts (PIV) rating. I'd guess 50volts would be adequate.

The difficulty might be building a unit in a suitable physical form.

I assume your motor does just have a plain rectifier and not a regulated rectifier. If you substituted a plain rectifier for a rectifier/regulator you would risk overcharging the battery.

Below is a digram that shows, in the top half how the three wire stator output (Yellow, yellow/grey and yellow/blue) can be used to supply AC to lights, and in the bottom half the basic circuit of the rectifier normally fitted.

I you can follow what I have said and can understand the diagram then go for it. If you dont then my advice, I am afraid, is to buy the proper replacement part.


BUT BUT BUT what engine are we talking about. In another thread you mention a 1978 55 hp . that only has a two wire stator out put and a three wire rectifier ... If that the case then back to the beginning ... just get a suitably rated full wave bridge rectifier. Connect yellow and yellow/blue to the AC input connections. Take DC out from the + and - connections

Click to expand...

Thanks vic. Although it is a mote point now that I have found a good used rectifier. Yes it is a 1978 55 hp 2 cyl johnson. According to my FSM it is a three phase output. Four wire rectifier. 1 red..b+, 1 yellow,1 yellow/grey, which the grey tach goes to,1 yellow/blue. So it does have a three wire stator, and not a two wire.Hope this clarifies and helps someone else,thanks.
Oh,and yes, the 78 55hp does not have a regulated rectifier.It puts out between 20 and 14 volts ac depending on rpm. At max rpm (5000) it only can produce about 5 amps,not a whole lot.

Re: Calling all rectifier gurus

And as a post scripe to this whole thread, after buying a good used one from my local boat mechanic. He told me I don't even really need to have a rectifier. My boat is a 13.5' 1958 nylox speedboat with a 55hp johnson. I have no radio,no stero,no depthfinder,no radar...no nothing. All the battery needs to do, if my motor and battery are in good shape, is to start it one time at the ramp. Which it will, on the first crank, and that's all I need to worry about. But I still wanted everything to work right. Oh, by the way,yes,it is fast. Very fast!!!

Re: Calling all rectifier gurus

Post , post script

OLDIRON said:

And as a post scripe to this whole thread, after buying a good used one from my local boat mechanic. He told me I don't even really need to have a rectifier. My boat is a 13.5' 1958 nylox speedboat with a 55hp johnson. I have no radio,no stero,no depthfinder,no radar...no nothing. All the battery needs to do, if my motor and battery are in good shape, is to start it one time at the ramp. Which it will, on the first crank, and that's all I need to worry about. But I still wanted everything to work right. Oh, by the way,yes,it is fast. Very fast!!!

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Do not allow your battery to become deeply discharged. Starter batteries do not take kindly to that and always recharge your battery as soon as possible after use. They do not take kindly to being left even in a partly discharged state.

Neglect you battery and you will soon be buying a new one with money you could have spent an rectifier which would recharge it as you speed along.

Re: Calling all rectifier gurus

Vic.S said:

Post , post script


Do not allow your battery to become deeply discharged. Starter batteries do not take kindly to that and always recharge your battery as soon as possible after use. They do not take kindly to being left even in a partly discharged state.

Neglect you battery and you will soon be buying a new one with money you could have spent an rectifier which would recharge it as you speed along.

Click to expand...

Agree ^^^