cost of rectifier

[d.tro]

1993 evinrude 70hp. My battery isn't charging. I have tested voltage while not running and when running at fast idle. No change. I'm guessing it's the recitifier. From what I have found online the part # is 193-4476. The cost varies from $150 to $175. What's up with that? Isn't that kind of excessive? All the other rectifiers are about $40. Is this one special, or have I been looking at the wrong part #?<br />Thanks

 

[rickdb1boat]

Re: cost of rectifier

d.tro <br /><br />Yes, the newer ones are more expensive. You can get one a the link below for $135.00. Good place for electrical parts.<br /><br /> web page

 

[Hooty]

Re: cost of rectifier

I read on another forum where you might be able to use a Radio Shack full wave bridge rectifier (p/n 276-1185) for about three bucks. It handles 25 amps 50piv. I'd give it a try, can't hurt anything.<br /><br />c/6<br /><br />Hooty

 

[rickdb1boat]

Re: cost of rectifier

Read these discussions about the bridge solution:<br /><br /> 013079 <br /><br /> 025571

 

[kart33]

Re: cost of rectifier

d tro<br /> Try here $126.95 https://www.surplusunlimited.com/storefront.htm

 

[John Reynolds]

Re: cost of rectifier

I wrote a little about the Radio Shack full wave bridge rectifier (p/n 276-1185 handles 25 amps 50piv). for $2.99 about a week or so ago. Any time you have AC (alternating current, like out of an alternator) and there are two wires going to the rectifier assembly, the rectifier is a full-wave bridge, which contains 4 diodes. If the alternator output consists of three wires, you probably have a full-wave rectifier (not a bridge) containing two diodes. You can see a schematic of a full-wave rectifier here: http://www.infodotinc.com/neets/book7/27c.htm <br /><br />The "triangle" part is an arrow, pointing to the cross-bar or line at the tip of one of the triangle's points. It's pointing to the bar because if current flows that direction (current flows from negative to positive) it is blocked. so for current to flow, negative must be at the wire connected to the bar, not the other end of the triangle. You can trace it out so that you can see that at the AC inputs, it doesn't matter whether or not an AC input at any point in time is positive or negative, it works out that the negative DC output is always negative, and the positive is always positive. THAT BEING SAID, A full-wave bridge rectifier is a full-wave bridge rectifier, no matter what the package it's in, only difference is the amount of power it can handle, and the peak-inverse-voltage (PIV) which is how high the voltage can be in the opposite direction from normal flow, and the current still be blocked. SO, if originality doesn't matter as much as price, go for the $2.99 radio Shack. It probably has a higher current rating anyway! But if you get close (maybe withing 20%) to it's maximum rating, better put a heat sink on it or mount it to something with heat-conductive grease. This full-wave bridge rectifier has a hole in the middle for a bolt to go through.

 

[Hooty]

Re: cost of rectifier

That's great John. Everybody loves beating the system.<br /><br />c/6<br /><br />Hooty

 

[d.tro]

Re: cost of rectifier

Thanks for the replies everyone. Wow I now have a headache trying to follow John's post and website. I think I'll pick up that RS part and maybe post a pic here of my setup and maybe John you can walk me through this.<br />Thanks again I appreciate it!

 

[John Reynolds]

Re: cost of rectifier

OK I'll try to help if I can

 

[d.tro]

Re: cost of rectifier

I've seen elsewhere that it's possible to test the rectifier itself by using on ohm meter and connecting to different leads (not the battery method). I just wanted to make sure that it was actually the recifier I'm looking at.<br />

 

[rickdb1boat]

Re: cost of rectifier

<br /><br />rectifier looks like this: Look on starboard(right) side of motor by trim relays.<br /><br />

 

[d.tro]

Re: cost of rectifier

That's what I thought, but I've followed the leads and I'm guessing it's like my wife tells me "it's right in front of your face stupid".<br />Why can't I find it.<br />

<br />

<br />hope I'm not bogging down the thread with all the pics

 

[rickdb1boat]

Re: cost of rectifier

<br /><br />Mine:<br /><br />

 

[d.tro]

Re: cost of rectifier

ok Rick did you just edit that post? Because the arrow was pointing at a bolt before, and now it's pointing at the heatsink? So it's under that heatsink?

 

[ob]

Re: cost of rectifier

d.tro,The arrow that Rick has pointed to the finned unit is your Reg/Rec unit.There is also a terminal post just to the left of this reg/rec that with the engine running you can confirm whether its red output lead is producing 13+ volts D/C.Don't trust just your boats voltage guage.It could be defective.The yellow and yellow w/ gray stripe wire are the voltage into rectifier from stator.The red wire exiting Reg/Rec is the D/C output.Touch one probe of a volt meter to the red wire on the terminal block and the other probe to ground when checking for voltage while running engine.The gray exiting Reg/Rec is for your tachometer and the purple is keyed 12V .The new style Reg/Rec does not have the purple wire any longer.

 

[d.tro]

Re: cost of rectifier

According to Joe 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 />I get readings in both directions so I guess it's bad.<br />I did buy the radio shack rectifier, but I don't know. Replacing a heavy heat sink with a thin silicon wafer??? I can get a used one for $50 and it's guaranteed to work so I think I'll go that way. Thanks for the help guys, amazing what pictures can do. I'll let you know how the "new" one works.

 

[John Reynolds]

Re: cost of rectifier

The Radio Shack rectifier has a bolt hole in it, and it can be mounted on the flat side of a heatsink. Some heat sink compound would need to be used, and R.S. also sells small tubes of it. <br /><br />A thing about ohmeters: On the regular ohms/resistance function (not diode test) of digital ohmeters, they may put out only .25 or .30 volts into the circuit. That's not enough to "turn on" the PN junction of a silicon device such as the diode. You need to exceed .7 volts. Use either the diode test function, or use an analog (meter needle type) ohnmeter.<br /><br />My old Mark 55E worked fine with the Radio Shack rectifier, and so did a friend's much newer model motor. But I think that the max output of my alternator is supposed to be at the most something like 7 or 9 amps of current, so I don't need a heat sink.

 

[bret walters]

Re: cost of rectifier

gentlemen, i would like to add an opinion to this thread that i do not want to be taken as a smart--- comment. if "d.tro" does have a bad reg/rect., which is yet to be seen why not install the correct part and repair the job in a professional manner. he will have save on the shop charges and the job will be right. personally i love t see jury rigged engines come in to my shop for repairs after they don't work, i get to sell the correct parts and do the job right and gain respect from that customer for doing what he or someone else could not, a quality job.<br />i enjoy saving money when i can and i do pass the savings to my customers but not at the cost of providing shoddy work. <br />the real question that needs to be answered is why did the rectifier fail, --- loose battery cable connections and corroded terminals is THE #1 cause. clean/replace the cable ends and battery terminal,throw away those stupid wing nuts on the battery and install s/s nuts and lockwashers tightly, install a new factory part, and go boating knowing some homemade part is not going to strand you on the water. P.S. if the factory part was to fail because of a defect it has a warranty and you can at least blame someone other than yourself.

 

[d.tro]

Re: cost of rectifier

ok "new" used one is installed. I am not seeing a jump in voltage from at rest to idling or reved. I am using a cheap analog meter that jumps from 10 volts to 50. The 50 is lowest and the lines from 10-15 are pretty close, but definate separation. I am not seeing any difference. Do I need to get a digital meter. Would I know if stator was shot? It runs like a top, or do I need to test for that.

 

[d.tro]

Re: cost of rectifier

ok It looks like I'm getting 15 volts AC from stator?????