No Spark after Stator Replacement

[RemingtonHoliday]

Hi all. Hoping to get some input on the problems I'm having with my 1984 Mercury 90 hp inline 6, with ADI.
Last year I had a problem where I couldn't get it to start unless I sprayed premix into the carbs, and then it would run, but basically couldn't get it above an idle.
I found that there wasn't spark on all cylinders, and I can't remember which ones. I did some testing and found that the Blue wire was bad on the stator. The trigger tested normal. So I ordered a CDI stator and then didn't get to work on it again until just recently.

I replaced the stator, and rebuilt the entire fuel system. Put everything back together, and now I don't seem to have ANY spark on ANY cylinder. I retested the new stator, and the trigger, which are all within DVA specs. One thing I did notice was when I tested the trigger with wires not connected to the switch box they were 4+ volts, but when I tested the same with the wires connected to the switch box, the voltage dropped to between 2 and 3 volts. I am not sure if this is a valid test with the wires connected to the switch box, or if it is any indication that the switch box is bad?

I find it strange that I have now lost all cylinders, and was wondering about the switch boxes, but I also find it strange that I'd lose all spark and both boxes are bad now.

Can anyone suggest any different testing I could do? I am going to try testing the coils.

Is there anything such as a wire or something that I could have loosened/disconnected by accident at the front of the motor when I had it apart for the carbs? That could have caused a no spark condition? I did try with the kill switch wire removed, and with the yellow rectifier wires removed. I had the big 7 pin connector apart and I cleaned it all up and applied dielectric grease, but I didn't think there was anything in there that would affect the spark, aside from the kill switch.

Do you usually test the trigger, stator, coils with them connected to the switch boxes? or disconnected?

Thanks for your time!

 

[RemingtonHoliday]

As an update, last night I picked up an online spark tester. With this I could see that there is spark on all cylinders, but weak on all 6. I get 0.5 -5 volts on 4 coils, and about 130v on other two coils. I tested voltage at the output from the switch box and got similar numbers. Could all test in specs for resistance.

So since my trigger and stator test in spec, I think I can fairly confidently say the switch boxes are both bad? Although a little odd to be both bad?

 

[Chris1956]

Is the new CDI stator compatible with the OEM switchboxes?

Also, the OEM switchboxes needed particular stator wires and trigger wires. These were banded together to keep them connected to the same switchbox. Does the CDI module have anything like that?

According to my '93 Merc V6 wiring schematic, the outer switchbox gets blu/white, red/white and red/white stator wires and trigger wires are brown, white and violet.

The inner switchbox gets blue, red and red wires from the switchbox and violet, white and brown trigger wires.

The switchbox bias wire is connected? The switchbox and stator grounds are good?

 

[RemingtonHoliday]

Sorry for the delay. I haven't been able to work on the engine until now. I acquired some used OEM switch boxes, and with them on, I now have good spark in all cylinders. So it seems the switch boxes were a problem.

Only thing now is that when I DVA test the output at the green wires , I get all 6 above 160V when I don't have the coil connected. But I get only readings in the 60s to 90s on all 6 when the coils are connected. According to the CDI manual I should have 150V+ with the coil connected. The coils test good according to the resistance testing.

I find it hard to believe that all 6 coils have an issue.

I also found that my rectifier is no good by resistant testing. Could this be causing the problem.

Is there any chance this is normal?

 

[Chris1956]

Bad rectifiers can cause spark issues. Disconnect the rectifier AC leads, insulate them and then retest DVA voltage.

 

[cyclops222]

So very correct !!!!!!!!!!!!!!!!!!!!!!!!
A shorted rectifier can overheat the coil wires under the flywheel. Causing them to burn open. With no voltage anymore..
A open rectifier can cause no voltage at the battery.
No hope. Must use a volt and a Ohm meter to do basic tests.