1990 Force 120 Stator and CD box Cylinders one and three no spark

[JWitt]

Hello all!
This is my first forum post ever. Firstly I would like to thank you guys for the wealth of information that you have taken the time to put on iboats! It has helped me tremendously getting my 1990 Force 120 up and running.

I have looked pretty deep and have not found this exact problem or answers so I thought I would ask.

•I currently have no spark on cylinders 1 and 3.

•The (5 year old CDI brand aftermarket) stator wires labeled 1 and 2 show ~215 volts. The wires labeled 3 and 4 show ~50 volts. Both circuits show matching Ohms. (The shop manual says replace stator, part has NOT been ordered)

• When disconnecting power to CD box 1 (cylinders 1 & 2) spark returns to cylinder 3. (CDI troubleshoot page says to replace CD box 1 if this is the case and part HAS been ordered)

So my questions are:
• Can a low voltage stator circuit permanently damage a CD box?

•Can a low voltage stator circuit give a false negative on a CD box?

•Can a faulty #1 CD box affect a stator output to CD box #2?

•Is it common or likely for a CDI brand stator to fail in less than 5 years?

Any help or advice would be greatly appreciated.
Thank you.

 

[JWitt]

Can a faulty CD box put a draw on the stator so it does not produce high enough voltage?

 

[Nordin]

Answers for all of your questions is yes.

 

[JWitt]

Well it sounds like I will install the new CD box when it arrives and test the stator outputs. Hopefully all tests = high voltage. Thanks for your response Nordin! I'll post my results. Any other responses that will help illuminate how and why the stator and CD can interfere with each other would be appreciated!

 

[Nordin]

There is a blocking diod in the CDI pack that can go bad.
It is blocking each other in some way, but I do not have it in my mind exactly how it works right now.
I have to up date my self by reading about it.

Will do it later.

 

[jerryjerry05]

A "new" stator can go bad in 1 day, even 1 hour.

Try unhooking the tach and see if spark shows up?

The blocking diode is explained below.


A stator can test good and still not work


Do the following test and let us know??

1. Resistance readings between the stator wire sets range from 680 - 800 ohms.
2. Disconnect the rectifier. If the engine fires, replace the rectifier.

1. Check stator and trigger resistance, trigger wire sets read approximately 50 ohms between the wire sets (DVA-4V or more), stator reads 680-800 ohms (factory) and 200- 300 (CDI/RAPAIR) DVA 180V or more from blue to yellow.
2. If readings are good, disconnect kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack.

 

[JWitt]

Disconnected rectifier and spark did not return.

Stator (CDI aftermarket) between blue and yellow resistance ran 316 ohms on both sets.

Trigger wire resistance all ran 52 ohms.

Disconnected cd kill wires independently (two test runs) looking for spark on cylinder #3, spark did not return.

Disconnected power to CD pack #1 1& 2 cylinders, and spark did return to cylinder #3

 

[Nordin]

Switch CDI pack #1 with pack #2 and see if the issue follows.
Do the same troubleshooting as you did before, disconnect power from #1 look for spark at plug #3 and #4.
Then connect pack #1 etc.
I think you have a bad CDI pack, #1 or #2.

 

[JWitt]

I'm pretty sure cd pack #1 (cylinders 1 and 2) is faulty. Allegedly the new one gets delivered tomorrow night. I'll swap it out with new one and retest both stator output circuits and spark. Fingers crossed the stator circuit showing 50 volts and 300 ohms shows ~200 volts!

If the new CD pack does not show, I will probably switch the existing packs and see if faults follow.

Does anyone have any schematics of the CD pack internal workings?

Thanks again for all the help and info. Sure did come to the right place!

 

[jerryjerry05]

"Does anyone have any schematics of the CD pack internal workings?"

Myself I've never seen one.
Try the swap.​

 

[Why Force it]

outboard mechanic tested my stator on my force 50 hp. 0e062441 and said stator is bad on one side. anybody know where I can buy one ? not available on this site. does not seem too hard to change if all wires are color code matched.

 

[JWitt]

So the new CD pack did not show up. I decided to follow your guys' advice and swap the two CD boxes.
​​​​
All faults followed the swap. Cylinders 1 and 3 still had no spark. Disconnecting power to one of the boxes brought cylinder #1 back to life (pre-swap #3 was revivable with power disconnect.). Also the stator "voltage drop" switched from blue and yellow set A to blue and yellow set B.

Feeling pretty strongly the new CD box will have me up and firing on all cylinders again. I'll post results after faulty CD box is replaced. Thanks again for all the help you two!

 

[JWitt]

Rockyal, I've had good luck with wholesalemarine.com and ebay

 

[JWitt]

Wholesale marine

 

[jerryjerry05]

Outboardignitiondotcom sells them new.
A little expensive but they're guaranteed.
Buying on ebay? make sure to use PayPal

 

[Why Force it]

Thanks, I did some more searching around and ordered one from franzmarine he has new and used both guaranteed. He claims to have more parts available for force motors than anyone. anyway, I hope this fixes my no spark problem.

 

[JWitt]

Well I put in the new CD box today and have beautiful spark on all four cylinders! Definitely surprised one faulty CD box can affect stator output and the other CD box! Good crash course on the ignition system. Thank you guys for all the help and guidance.

Now link and sync + carb tuning. Thanks again!