CDI OR OEM STATOR?

b75nweav

Cadet
Joined
Jan 5, 2007
Messages
11
WELL, FINALLY BROKE DOWN AND DECIDED TO GET A NEW STATOR. IVE BEEN SHOPPING AROUND AND FOUND A COUPLE. ONE IS OEM #398832075A20 FOR $325 AND THE OTHER IS CDI# 1745454K1 FOR $159. WHATS THE DEAL, IS THE CDI A PIECE OF CRAP OR IS IT WORTH THE MONEY. ALSO NEED THE SWITCH BOX AND RECTIFIER. OYEA, MY MOTOR IS A 1987 MERCURY 50HP 4CYL. SERIAL NUMBER IS 6589701. STATOR WAS BAD WHEN I BOUGHT THE BOAT, SALT WATER CORRODED THE CHARGING WIRE, NO BIGGIE THOUGH JUST USED MY BATTERY CHARGER ALOT. WELL IT FINALLY TOOK A DUMP AND MY BOAT MECH. SOLD ME ONE OFF A USED 50 HP HE HAD IN HIS YARD. (DONT EVER LET THEM DO THAT, TAKE IT FROM ME). MOTOR HASN'T WENT OVER 3000RPM IN ABOUT 6MONTHS. JUST PUTTING AROUND. MECH SAYS THE HIGH SPEED WINDING SIDE IS BAD. SOUND RIGHT TO ANYONE? SOMETIMES A LITTLE HARD TO CRANK BUT ALWAYS DOES, ONCE RUNNING I CAN GO ABOUT 8MPH. ANYWAY I WOULD APPRECIATE ANY SUGGESTIONS ON THIS SO I CAN PURCHASE PART ASAP. NEED FOR SPEED!!!!<((((((((<
 

Mike722

Petty Officer 1st Class
Joined
Nov 7, 2005
Messages
370
Re: CDI OR OEM STATOR?

From what I have seen here, most believe the CDI's are better than OEM. I installed a CDI on a 1994 40hp 4cyl. last year. Low side was bad, no spark to start. It was hard to start, but ran fine once it started, for the 2 weeks before it quit all together.
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: CDI OR OEM STATOR?

CDI componets are light years ahead of OEM, but test the system before buying parts
 

b75nweav

Cadet
Joined
Jan 5, 2007
Messages
11
Re: CDI OR OEM STATOR?

WHY ARE THE OEM PART SO MUCH MORE. THE CDI LOOK KINDA CHEAP WITH NO INSULATING WRAP ON THEM. WHAT DO YOU MEAN BY TEST THE SYSTEM. I HAVE GREAT SPARK ON ALL PLUGS, OK COMPRESSION 110 ON ALL CYL, REPLACING STATOR, SWITCH BOX, RECTIFIER JUST BECAUSE I WAS TOLD THAT IS THE BEST WAY TO DO IT. IS THAT RIGHT.? WOULD HATE TO REPLACE THE STATOR JUST TO HAVE THE SWITCH BOX BURN UP A WEEK LATER. .........THINK I'LL GO WITH THE CDI THEN........LET YOU KNOW HOW IT TURNS OUT........
 

Mike722

Petty Officer 1st Class
Joined
Nov 7, 2005
Messages
370
Re: CDI OR OEM STATOR?

I agree with Laddies, you need to test all the system componets before replacing anything. Electrical parts are not returnable.

I paid my mech to test the system (about 60 bucks) and then I replaced the parts needed myself. I was told the CDI stator does not have the wrap because the wrap holds too much heat and heat is what kills the stators.

You will need a good manual, if you do not already have one.
 

ricksrster

Commander
Joined
Jun 19, 2005
Messages
2,022
Re: CDI OR OEM STATOR?

Here is some resistances you can check with an Ohm meter.
OEM stator: Blue to ground = 3250 -3650 Ohms.
Red to ground = 75-90 Ohms.
Trigger: White/black to brown = 800 -1400 Ohms.
White to purple = 800 - 1400 Ohms.
Coil: Primary = 0.2 - 1.0 Ohms
Secondary = 800 - 1100 Ohms.
If you access to a DVA voltmeter we'll get you the peak voltages for the stator and the trigger.
Your Rectifier should only show continuity in one direction between each yellow wire post and the red post.
 

DHPMARINE

Captain
Joined
Dec 16, 2003
Messages
3,688
Re: CDI OR OEM STATOR?

CDI is a reliable source.Some of us know it as Repair,Inc. which has been around for a long time.Two years ago I spoke with one of their reps,(he was really down to earth).He explained the "stripped down" stator is to reduce heat,and that is what kills Merc's units.

But you do need testing to be sure your's is bad.

DHP
 
Joined
Jun 1, 2010
Messages
18
Re: CDI OR OEM STATOR?

What most people DONT KNOW is, stators are fairly easy to rebuild!!! The problem with the older ones is, they are sealed in heavy insulated plastic. This makes repairing dry rotted wires "almost" imposible without totally rebuilding. You have to physicaly remove the covering to exposs the coils and wires. If you have one of those newer style ones, DO NOT THROW IT AWAY!! Odds are, only one or two coils may be bad. 75% of the time, it is the low speed coil that go out first. This will cause a weak spark/no spark issue. When the highs go out, you may be able to start it, but when you increase throttle, it will lose spark and stall. Coils can be checked with an ohlm meter. (I want to also add, if you have one of the older engines, REPLACE EVERY WIRE IN THE ENGINE! I have all the diagrams for my engine so I just use red and black for everything. You can also tag each wire as you install 1 at a time. I have brought numerous engines to life without buying a single part!) It always ended up being a dry rotted wire somewhere. If you find a bad wire, DONT PATCH IT, REPLACE THE ENTIRE WIRE! If you bend the wire and it cracks, replace it!!!!!!! Just by running your engine with a bad wire, you can fry every circuit in your ignition. Especially the stator and switchbox. One thing everyone misses on any outboard engine is the water impeller. Just because it is spraying water does not mean it is fully functional. Electrical parts ARE KILLED BY HEAT! When impellers start to go bad, pieces can break off and become stuck in the passage ways. This will restrict water flow and make your engine run hotter. $25 is a small price compaired to a $300 switchbox. Not to mention a cracked head. I change mine every year and blow air through the passage ways.
They sell single coils online. For instance, my low and high speed coils are (174-3175 and 174-3176). The problem is, they want upto $50 each. I found them as low as $20. A lower price could mean less quality. Once you understand how something works, you can fix it. A stator/coil is nothing more then coated, copper wires! There are no circuits or sensors, just copper wire!!!!! The wire works with the magnets to create "ELECTRICITY"!
Hopefully someone can use this info.
 

sschefer

Rear Admiral
Joined
Nov 13, 2008
Messages
4,530
Re: CDI OR OEM STATOR?

I don't believe Merc is making the stators for older motors anymore. I don't have any proof but judging from the last Merc Stator that I bought from Merc and comparing it to an identical CDI there wasn't any difference.

What you get from Merc when you buy their parts is the guarantee that it is the correct part for your motor and Merc standing behind it. I don't think it's necessary but you pay for that luxury at nearly double the cost. Not worth it to me, I'm perfectly capable of ordering the correct parts for a motor that's out of warranty anyway.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,931
Re: CDI OR OEM STATOR?

For instance, my low and high speed coils are (174-3175 and 174-3176).
:confused: These fit a 50hp ignition driver distributer and wont fit a 850hp... :confused:

A stator/coil is nothing more then coated, copper wires! There are no circuits or sensors, just copper wire!!!!!

Basicly thats correct but the high speed and low speed coils has different size wire as number of windings and the guage of the wire effects output of coil. The greater the number of turns in the coil will increase the amount of magnetic flux cut by the coil which will increase the electrical output. Also the thicker the wire the more amps the wire will produce. Also the coils themself vary from stator to stator as the amp rating changes, the higher the rating the thinner the lamnations to reduce output due to increased magnet size, that the reason there are shunt plates on the front of 40 amp low speed coils,it basicly sheild the coil and acts as a shorted winding ,if not that coil could produce in excess of 2000 volts at rpm:eek:
 

Ferobin

Cadet
Joined
Apr 10, 2011
Messages
6
Re: CDI OR OEM STATOR?

im not so pleased with my cdi stator 174-5454k1.I replaced mine with a brand new one only because the wires wore on the old one and the motor started right up.then the next day i tried again only to find i have no spark.i should have left it alone as it was running fine just hard starting.not sure what path i will take now,maybe take captains advice and change only the low speed winding.first ill need to find the part number for the coil.
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: CDI OR OEM STATOR?

im not so pleased with my cdi stator 174-5454k1.I replaced mine with a brand new one only because the wires wore on the old one and the motor started right up.then the next day i tried again only to find i have no spark..

Defective new parts can happen with ANY manufacturer, some rarer than others, but it can happen.

CDI has written and published a FREE Ignition Troubleshooting Guide, probobaly one of the finest, use by most all techs.

Follow the direction, troubleshoot your ignition, if you even THINK their stator has a problem, CALL THEM, they are great people that really care about the quality of their products.

If a CDI product fails within a short time they will OFTEN stand behind it and make it right.
 

Ferobin

Cadet
Joined
Apr 10, 2011
Messages
6
Re: CDI OR OEM STATOR?

ok.the motor ran fine to begin with just charging issues,so i changed stator without testing anything.MISTAKE NUMBER ONE.the motor did start and run for about five mins and was fine. both coils read bad according to cdis tests.MISTAKE NUMBER TWO,i removed both coils without consulting cdi.now what i need to know is can i relace only the 2 coils on 9 amp stator 174-5454k1?the rest the stator is fine. IM not sure what two coils by part number to replace them with.I found coils online but dont want to make another costly mistake.it seems a simple fix but connot find parts listing for a stator its self only for a whole new stator.CDI may produce qaulity product but i was suprised at how quickly it burnt up.some help from someone with more experiance would be greatly appreciated.
 
Top