What would ruin both ig. coils?

Both the coils from my 750 SECA are dead. Infinite resistance from plug wire to plug wire. Did high voltage from the regulator cause this? I put the couls from my 550 into the 750 and it started up, the plugs fouled and it stopped. I cleaned off the plugs, and now I just get a few fires and out. Will these coils be ruined also? I'm getting closer to the problem. Thanks! Bill

 

I can't think of much that would burn out the secondaries... maybe cranking for a long time with bridged gap plugs?

Have you removed the caps before checking resistance? Basically want to know whether it's the secondary/wires that are open, or the caps. If you find that the caps are OK, you could always try the Dremel wire swap in case it's the wires and not the coils that are the problem.

 

Ohm out the primary windings on the coils (the pigtail you plug the harness into). You should see about 3 ohms. If you do, you can salvage the coils by replacing the high tension leads using the dremel method mentioned by SQL. I have opened up 3 sets of coils and have found that the coil failures have been exclusively the high tension leads. A cheap fix is some coil/ignition wire from Napa, ensure that it is the copper core, not the carbon filament.
It sounds like you are fouling out plugs, are you sure your carbs are happy? Properly gapped? Correct plugs?

 

I'm getting less than 2 ohms. I'm taking the carbs out for a look over for sure.
"I can't think of much that would burn out the secondaries... maybe cranking for a long time with bridged gap plugs?_SQLGuy"
Maybe cranking too much with fouled plugs? I don't think I did it that much, but maybe. Thanks. Bill

 

I'm voting failed wires (if you took the caps off first.)

 

So answer me this: Why would all the wires fail? Or at least one from each coil?
[Why do I have to be the pioneer around here for wacko issues? :roll: ]

 

Answer me (and everyone else) this:

Did you measure the secondaries with the plug caps off? If so, what was the result?

As to why both coils would have wires would fail at the same time:

1. They were made at the same time and have exactly the same type of rot going on inside them that finally made them fail? Unlikely, but possible.

2. Someone one pulled on them in an inappropriate manner recently? More likely.

3. The procedure used to measure the resistance of the secondaries was incorrect? Most likely (IMO).

 

Lighten up jerk! IMHO.
Bill

 

Why do you ask for help and then not provide information that people need to help you?

I am dead serious that I still think the most likely explanation for both of your coils suddenly measuring as bad is that you didn't measure them correctly. The fact that, after several requests, you STILL haven't told us whether you measured them with, or without, the caps on them significantly reinforces this belief.

Sorry if I come off as a jerk. I probably am one. But I am trying to help you.

 

After getting inconsistent results testing the Coils ... you have to take a "Leap of Faith" and replace the Spark Plug Wires.

The Wires are attached to the Coil when the Coils Casing is applied.
To access and replace the Wires ... you have to REMOVE Coil Case material.


From 3/4" behind where the Wire emerges from the Coil ... Case material has to be removed to EXPOSE the Wire and the Terminal End which protrudes from the back ... onto which, the Center of the Spark Plug Wire is attached.

One Tungsten Carbide Dremel Bit is all you'll need.
Remove Case Material exposing as much of the Old Wire as possible.
Use Needle Nosed Pliers to pull the wire away from the inside of the case.
Pull the Wire Out.

Inserting New (or used) Wire

Cut the End of the wire on a Bias (angle)
Smear a film of Grease on the Wire
Insert and twist until ther is enough to grab with Pliers.
Prep the END of the New Wire to make CONTACT with Coil Terminal.



You can acquire High Quality Wires at a Junk Yard out of a Beemer, Audi or VW.

 

Excellent photos Rick! You should work for NASA.
Bill