Rectifer woes with CDI/Rapair stator

andy6374

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Aug 4, 2005
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This is an update post for my rectifier problems.<br />Background:<br />I have an 88' V6 200hp merc (Serial # 0B303415). My stator recently went and I replaced it with a CDI/Rapair (CDI P/N 174-5456). This is "supposed" to be a 9 amp stator. However, my mercury rectifier (MERCURY RECTIFIER # 5707 ,OE # : 62351A, 62351A2) and new replacements of the same OEM numbers are pumping out 17+ volts. If I run all the electronics I can get it down to 14.9 V (still to high).<br /><br />Should I get a CDI rect/reg. What number?<br />I thought if its just a 9amp stator then I don't need a regulator. What's up with these CDI/Rapair stators, aren't they compatible? Anybody else have similiar problems?<br /><br />-thanks<br />andy
 

dakk1

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Apr 22, 2003
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Re: Rectifer woes with CDI/Rapair stator

Andy<br /><br />I have the same stator that you have on my 1985 Merc 150hp. CDI states: <br /><br />"CDI has developed a line of stators that are very reliable on the Mercury Marine outboard engines. We use a heavier gauge magnet wire on the capacitor charge coil, which allows more current to flow. More current flowing equals less heat in the windings. This heavier magnet wire also creates less resistance in the windings. <br /><br />These stators also have voltage protection on the low speed coil to protect from over-voltage issues"<br /><br />If all of this is true, and you are using a marine type battery, perhaps you are operating within safe parameters. My concern would be other electronic accessories such as fish finders etc. You and I are in the same boat, so to speak. Pun intended.<br /><br />Dave..
 

andy6374

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Re: Rectifer woes with CDI/Rapair stator

So, you too are overcharging. Not only is it bad for the electronics, but it will fry the batteries. How can this be stopped? I am not comfortable knowing that I could possibly burn out a $650 GPS unit along with VHF radios, fisherfinder,running lights, panel lights....everything.<br /><br />Safe parameters would be more like 14.2-15.2 volts, but 17+ volts is crazy.<br /><br />Any ideas?<br />-Andy
 

Laddies

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Sep 10, 2004
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Re: Rectifer woes with CDI/Rapair stator

Buy a voltage regulator if you want to cut the voltage back its not a big deal to install and done all the time on racing engines
 

andy6374

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Re: Rectifer woes with CDI/Rapair stator

I contacted CDI\Rapair and this is the conversation we had:<br /><br />CDI:<br />""The 174-5456 is a 9 amp charging system but if you use any battery other than a deep cycle acid marine battery then the voltage will not be regulated. The stator and rectifier does NOT regulate the current or voltage on nine amp systems only the battery does. A maintanance free,or automotive cranking or Glass mat battery is not a battery that you can use without a regulator. If the problem persists then you will have to install a regulator."<br /><br />ME:<br />""Thanks for the quick reply. However, I do have two deep cycle marine batteries. And both of them are getting overcharged, using one battery at a time. Do you have a recommended rect/reg. to rememdy this problem, what is the P/N #? However, this problem started exactly when I installed the new stator, what do you think the problem could be. ""<br /><br />CDI:<br />""Again the type of batteries make most of the difference, Also if there is no current useage in the boat then the battery will overcharge. If we could put out more amperage; then there would not be a use for the big flywheels and 35 amp stators. The regulator recommended is a 194-5279 for almost any charging system up to 20 amps. Also if you run long preiods at high rpm then the batteries may over chadrge if you do not have any drain on them. ""<br /><br />Is it true the battery should overcharge if I am not using the any instruments. My opinion is that I shouldn't have to run all the electronic accessories on the boat to "tame" the voltage input to my instruments. Especially with a 9 amp stator.<br /><br />But under Laddies recommendation, I am going to get a regulator. However, if I new this was going to be the case I would have purchased a 16 amp stator.<br /><br />-Andy
 

andy6374

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Re: Rectifer woes with CDI/Rapair stator

Well, I also just found out from CDI/Rapair that poor deep cycle acid battery. I told them my battery brand and they said it wasn't a true "deep cycle acid marine battery" and has thin plates. And that it can't regulate the unregulated system. I already order a reg., but i will try the setup, w/out reg., with my buddy's battery and see what happens.<br /><br />-thanks<br />andy
 

DHPMARINE

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Dec 16, 2003
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3,688
Re: Rectifer woes with CDI/Rapair stator

Just my 2 cents worth.<br /><br />I see three stators listed for your engine.One seems NOT to have a rectifier or regulator.The other two need you to measure thickness of the stator.<br /><br />Maybe forget for now what CDI says,go back to basics,and see if you have the correct stator to begin with.<br /><br />DHP<br /><br />We can go from there.
 

andy6374

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Re: Rectifer woes with CDI/Rapair stator

Yeah, before I dived into this mess I made sure I had the right stator. My marine mechanic confirmed this himself. He said that even merc stators will overcharge if you have a poor deep cycle acid marine battery. I am going to try the setup today with my buddy's Optima Bluetop D31M deep cycle battery to see what happens.<br /><br />-Thanks<br />andy
 
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