1989 50 HP Force One cylinder not firing

Force8950

Recruit
Joined
Jan 30, 2019
Messages
3
Hey guys, been looking st a lot of previous posts on this issue but I still can't figure it out. I've got a 50hp 1989 force that only fires on one cylinder. I've read the DCI trouble shooting guide multiple times and still cant figure the issue out. I'll go through everything I know. Bear with me, I've tried a lot. Ok.

1) The flywheel: all magnets are in place and when I run a screw driver around it I feel pull everywhere and no weak points that I can identify. Also no play in them. And the timing key is present and good.

2) The stator. The white sets all read within proper resistance, and I have a DVI adapter, and both output sets (blue black brown and yellow black brown) both put out 250v when it's running. I'm pretty sure that it's good. Swapped wire sets just to be sure and no change on which plug was firing.

3) Rectifier: DCI says to disconnect the rectifier, if it starts firing that's the issue. Nothing changes when I disconnected the red charge cable.

4) Coils: if I swap the coil cables coming off the DCI box the issue moves from one to the other, so I know both coils can fire.

5) Trigger: thought this was the issue, but I bought a new one and same issue. When running I measured the voltage and this is what i got. CDI box left and trigger right. Nothing changed with the new trigger.

Yellow to Yellow brown 1.6 set 2.
Green to Green brown .6 set 1
Orange to Orange brown 2.5 set 2
Red to Red brown 1.3 set 1

I marked the sets that correspond to each coil.

I then rearranged the trigger cables to swap sets to see if it would move the issue, and it didnt, here is that voltage test.

Yellow to red brown 1.3
Green to yellow brown .6
Orange to green brown 2.4
Red to orange brown 1.3

I find it very interesting that even though the trigger sets are swapped the over all voltage didnt change on the CDI box wire side... I also dont know, is that the voltage coming from the trigger or from the trigger and DCI as a combo? Unsure of how that works.

that leads me to the DCI box.

6) DCI box. I dont really know how to test this. I've taken off the kill wire, and that didnt change the issue at all. There is an orange and red cable going to the coils, one per. When swapping the trigger cables only the orange one fired both times. This is also my second DCI box (used off Ebay. So no guarantee that its 100% but the seller claimed it was off a good motor) I haven't had a chance to test the original one the same way as above to see if there is a change, but I really dont want to buy another DCI just to have the same issue.

is there any other tests that you guys can think of, really need some guidance on this one. Thanks.
 

Nordin

Commander
Joined
Jun 12, 2010
Messages
2,428
In my eyes it sounds like your CDI box has one bad output channel.

The ignition system contains a trigger which gives signal to the CDI box to discharge the capacitors to spark the plugs and you have one new now.
Looks good.
A stator which charge the capacitors in the CDI box and one channel is sparking and the input from the stator to the CDI box is 250VDC measured with a DVA adapter.
Also looks good.

The only thing left is the CDI box, you can not measure it. If trigger signals is correct and stator voltage output from stator correct.

One thing you should do is to check the wires at the terminal stripe. The shrink tube at the luggs can hold the wire in Place and it looks like good BUT the thin wires are loose under the shrink tube.
Pull the wires by holding in the wire insulation when the terminal screw is unscrewed and check.
 
Last edited:

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
The 50 can start and run on 1 cyl.
Does it start?

You swap the coils to see if the spark follows the coil?
You can swap the lead(red/orange) to the coils from the pack.
You check the plugs?

Spark: you have the spark tester that measures the strength? How strong?(see pic)
shopping



Flywheel, the magnet is one solid strip, it can break loose and cause a problem,
I don't think this is the case.

Flywheel key. The only way to check it is remove the flywheel.

A stator that tests good??? can be bad.

Said he installed a new trigger.
 

Force8950

Recruit
Joined
Jan 30, 2019
Messages
3
I've checked the terminal connections, I read about the shrink tube issue. When I checked (few weeks ago now, my stator connections were in pretty poor shape under the stink tube, redid the connectors on all including grounds that go to the block.

As for running, it idles and runs great, I didnt notice one cylinder wasn't firing until I got it on the water and at WOT it wouldn't go, it felt like half power or less. After a little investigation I found that one had no spark. I then double checked by disconnecting the non sparking wire from the plug, and it started and ran like usual. Then I put it back on and took off the other wire and it cranked and didn't even cough. So definitely no spark to it and that's when I realized it had been just running one cylinder.

I'm probably going to have to order a new CDI. Also all voltage tests above were with a DVA adapter.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
You try swapping one coil with the other?

Testing the pack?? There really isn't a way to test it.
The Outboard Ignition techs says to test everything else and if they test OK??
Then it has to be the pack.

If you buy a new /used coil ?
Make sure it's for a 50
The plug wire on the 85/90 120/125 are shorter.
 

Force8950

Recruit
Joined
Jan 30, 2019
Messages
3
Ordered and installed a new CDI box finally. Fixed the issue. Turns out the first one I baught used was broken. Lesson, dont buy used electronics.
 
Top