1970 1150 rectifier or "radio shack full wave"??

Joined
Sep 19, 2007
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I've seen posts on this and don't know which way to go...I've heard of great luck with the radio shack full wave replacing the rectifirer and is cheaper and holds a constant voltage to the battery better...what do you guys think?? pros and cons?? Will replace before putting on my new stator. Thanks again!!
 

ricksrster

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Re: 1970 1150 rectifier or "radio shack full wave"??

you could buy 3 Radio Shack bridge rectifiers and still save a bunch of dough and have a couple spares in case the battery becomes disconnected while the motor is running.
The Mercury Rectifier is basically the same thing only it costs a whole bunch more. It is just 4 diodes in a case.
 
Joined
Sep 19, 2007
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Re: 1970 1150 rectifier or "radio shack full wave"??

thats what I wanted to know, thanks alot!! Do you have a part number for that?? I'll order it online...does it mount much the same or do you have to make a mount for it?? Do you have a picture of it?? thanks again!
 

j_martin

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Re: 1970 1150 rectifier or "radio shack full wave"??

you could buy 3 Radio Shack bridge rectifiers and still save a bunch of dough and have a couple spares in case the battery becomes disconnected while the motor is running.
The Mercury Rectifier is basically the same thing only it costs a whole bunch more. It is just 4 diodes in a case.

Except the mercury rectifier is barely adequate and has no room for such foolishness as a dirty battery connection. A 400 volt, 25 amp bridge rectifier will survive anything you can throw at it. Just mount it to the aluminum plate tight so it can stay cool, which is defined as not hot enough to light a cigarette.

hope it helps
John
 

david watson

Cadet
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Sep 20, 2007
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Re: 1970 1150 rectifier or "radio shack full wave"??

hi to whom it may concern
i have had this boat now for about 2 yrs it has got an old merc blue band 1000horse(100hpsix) it goes quit well but i am after a rebuild manual for it and is it worth rebulding after it die,s .i,ve put it in salt water about 6 times otherwise in freash water can anyone help me
 

ThumbPkr

Petty Officer 1st Class
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Aug 17, 2007
Messages
371
Re: 1970 1150 rectifier or "radio shack full wave"??

I would say by looking at it that the rectifier that came with the engine is a selenium rectifier and the full wave bridge bought at Radio Shack will have silicon junctions and the electrical difference between the two is that there is a larger voltage drop across the solid state junctions with the selenium rectifier than there will be with the silicon rectifier.
That can be significant in a critical circuit such as substituting one technology for another when replacing a transistor but in the case of a full wave bridge the end result might leave you with a few tenths of a volt higher charge in your battery when comparing the two in favor of the silicon rectifier.
It should not be a concern in that application.Use a good heat sink and silicon grease to transfer the heat properly and it should work without any problems.Ron G
 

jimg984

Chief Petty Officer
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Jul 16, 2007
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403
Re: 1970 1150 rectifier or "radio shack full wave"??

i would like try one these on my 1978 inline 6 115HP......... does anyone know a part number for this or know what to ask for?

thanks
jimg984
 

Chris1956

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Mar 25, 2004
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27,033
Re: 1970 1150 rectifier or "radio shack full wave"??

Johnny, You will need to make some simple wiring changes to use the radio shack rectifier. You need to ground the neg DC pole of the rectifier to the case of the outboard. You also need to change the three ring terminals of your outboard wiring harness to female spade terminals, You can get these from radio shack as well.

I mounted the rectifier on the front cowling support, where my original rectifier had been.
 
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Re: 1970 1150 rectifier or "radio shack full wave"??

Well I think I'm going to go with the full wave 25 amp and make an aluminum plate for it and find an old heat sink from a computer for it. What kind of voltage are you guys seeing out of these?? I would rather not go over 14 to 15 volts to keep from shortening the battery life. I know kind of how these work and I guess you can't use a regular voltage regulator as you have to change from A/C to D/C voltage...is this true? Are there different types of "radio shack" models that will give me different voltages to the battery?? How will I adjust this or is that possible?? Also, sorry for all the ques...I'm going to put together and install with pics and results of what I get at varying rpm's. Now the other question, where do I install my tach wire on this?? can it go on either of the A/C posts coming from the stator?? Thanks again for you help.

As for the post above about are they worth it?? I am a research nut...and have done ALOT of digging on various motors...SOO many people have said to use my 1150 as a black anchor....but I love the motor...very simple in design and very tough. You know something was done right when after nearly 40 years it will push an 1100# boat 40mph. I have problems don't get me wrong but they are simple. There are expensive parts but there are only a few of them...not ALL kinda of little sensors and electrical jewels...just simple "fire, fuel, and air". I would say do a compression test, do a decarb if you haven't already, link and sync and if all checks out let her bump. These engines were made with pride...not with cutting corners and "lowest bidder". Many people don't like the inlines but you HAVE to understand them and they do like TLC. I say go for it!
 
Joined
Sep 19, 2007
Messages
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Re: 1970 1150 rectifier or "radio shack full wave"??

mine doesn't have a wiring harness...everything is hard wired and goes through a vacuum line off a John Deere combine...works perfect and seals great. yeah its a pain if I take the engine off...but how often does that happen? lol Thanks for the info...I have I've made spades out of the rings before just take angle cutters and snip the ends off and you have spades that will still fit around a stud. Thanks for your help...this site is AWSOME!
 

j_martin

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Re: 1970 1150 rectifier or "radio shack full wave"??

Quote>>>>

Well I think I'm going to go with the full wave 25 amp and make an aluminum plate for it and find an old heat sink from a computer for it. What kind of voltage are you guys seeing out of these?? I would rather not go over 14 to 15 volts to keep from shortening the battery life. I know kind of how these work and I guess you can't use a regular voltage regulator as you have to change from A/C to D/C voltage...is this true? Are there different types of "radio shack" models that will give me different voltages to the battery?? How will I adjust this or is that possible?? Also, sorry for all the ques...I'm going to put together and install with pics and results of what I get at varying rpm's. Now the other question, where do I install my tach wire on this?? can it go on either of the A/C posts coming from the stator?? Thanks again for you help.
>>>>>>

The difference between rectifier junction voltage drops, like 2-3 volts for selenium, and 0.5 - 0.8 volts for silicon is insignificant compared to the no-load supply of 70 volts or more available from the stator. The current is controlled by the stator, as it can only put out so much, and the voltage will drop to limit that amount. It's in the 12 - 15 amp range. The voltage is limited by the battery. It uses the excess current to hydrolyze water into hydrogen and oxygen. That's why batteries need ventilation, and also why they use water. Eventually this destroys the battery, but it takes a couple of years.

If you install a bridge rectifier, the stator wires go to the terminals marked either AC or ~, the - terminal is grounded, and the + terminal goes to battery. The tach hooks to either stator wire.

You can retrofit a voltage regulator from a later Merc motor, either a 16 amp, or one of the 2 in a 40 amp dual coil system. Yellow goes to stator, red goes to battery, and grey goes to tach. It needs reasonable heat sinking, so bolt it to something aluminum, not plastic. That has a cost of a little over $100, but takes a little load off the stator and lengthens battery life. Use an aftermarket one. The Merc regulators are notoriously weak.

hope it helps
John
 

emckelvy

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Jan 16, 2004
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2,506
Re: 1970 1150 rectifier or "radio shack full wave"??

Here's a link to the Radio Shack Rectifier:

http://www.radioshack.com/product/i...roductId=2062584&support=support&tab=features

BTW it worked great in a Honda Trail 90 too!!!

And if you want to go "low tech", you could always keep your running lites on, this should be enough load to limit voltage to a reasonable level.

If you're handy with electronics, you could build your own Zener Diode voltage regulator:

http://www.reuk.co.uk/What-is-a-Zener-Diode.htm

http://www.reuk.co.uk/Zener-Diode-Voltage-Regulator.htm

Cheers.........ed
 

gonelong

Seaman
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Mar 9, 2007
Messages
65
Re: 1970 1150 rectifier or "radio shack full wave"??

Johnny, You will need to make some simple wiring changes to use the radio shack rectifier. You need to ground the neg DC pole of the rectifier to the case of the outboard. You also need to change the three ring terminals of your outboard wiring harness to female spade terminals, You can get these from radio shack as well.

I mounted the rectifier on the front cowling support, where my original rectifier had been.

From this I gather I could make a black wire with a spade terminal to plug into the (-) post of the rectifier, and a ring terminal on the other side and then connect that ring terminal with the one from the harness (also black ground wire) and secure them to any ground on the engine?

What gauge or type of wire would I need to do this? Could I pick up something from an auto-parts store that would work?

Do you simply splice the yellow & Grey wire together into a single spade terminal? Same gauge & type of wire as above? These wires are a bit short, so I may have to extend them first, and then combine them.

GL
 
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Re: 1970 1150 rectifier or "radio shack full wave"??

gonelong...I just got my full wave today...I order two and cost 6 bucks. I'm doing mine tommorrow and will post what I do and the results soon. The full wave has four spades on it. One ground, one hot, and two that you will put your A/C current to from the stator. Doesn't matter which goes where...you will just have to splice into them or make longer wires from the plastic insulator on theside of the block. The full wave is MUCH smaller than I expected...and will be VERY easy to install and will clean up under hood a bit. I should have my pics and all up sunday. I think this will be the way to go...and it'll handle alot more abuse than the original...not to mention its smaller, simpler, and WAY cheaper...you could by 10 for the price of one merc rectifier.
 

jimg984

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Joined
Jul 16, 2007
Messages
403
Re: 1970 1150 rectifier or "radio shack full wave"??

I have been following your progress on this rectifier job. i wanna do mine that way. so if will keep it posted it sure would.. i realy think its the way to go... so your help would be apperecaited

jimg984

115 tower of power
 

jimg984

Chief Petty Officer
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Messages
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Re: 1970 1150 rectifier or "radio shack full wave"??

we been waiting to hear from you.. did you get shocked?? J/K=just kidding
 

j_martin

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Sep 22, 2006
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7,474
Re: 1970 1150 rectifier or "radio shack full wave"??

I just ripped the 40 amp experimental stuff off my XR4 and put the 16 amp back with the aftermarket rectifier. I'll snap a picture tonight and post it.

I fashioned loops from 14 gauge solid wire and soldered them to the tabs on the rectifier. Then I used stainless machine screws and nuts to fasten the original ring tongue wires to it in the prope places. The neg terminal has a piece of 14 g solid wire soldered to it and looped so it goes under one of the mounting screws for the aluminum plate I made to fit the original mount.

It's well mounted, wired tight, and reversible.

hope it helps
John
 

jimg984

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Re: 1970 1150 rectifier or "radio shack full wave"??

john, didn't the radio rectifier work or did you not like it?,,,,,,pics of your work would be helpful
 
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Re: 1970 1150 rectifier or "radio shack full wave"??

As far as I recall the semiconductors are silicon and germanium. Silicon will yeild a .7v drop across the junction and germanium will drop .3v across the junction. In a full wave bridge rectifier you have 4 diodes and are always flowing thru 2 at a time so if the rectifier was silicon you would lose 1.4v at the output and .6 if it were germanium. Didn't know selenium could be used and therefore have no idea what the voltage drop accross that junction would be.
 

j_martin

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Re: 1970 1150 rectifier or "radio shack full wave"??

john, didn't the radio rectifier work or did you not like it?,,,,,,pics of your work would be helpful

It works well. That's what I put back on after both of the 20 amp regulators from Mercury failed in service.

Picture attached
Upper left (AC)
1 yellow to stator
1 to regulator

Upper right (+)
1 to battery
1 to regulator

Lower left (-)
ground under mounting screw

Lower Right (AC)
1 yellow to stator
1 grey to tachometer

hope it helps
John
 

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