How do I remove the spark plug wire from a coil?

[Boatleech]

This is undoubtedly a dumb question, but what's the secret to removing a spark plug wire from a coil on a 40HP AD-CDI Mercury? I slid the boot back, and see the ignition wire has a small Ty-Wrap on it about 3/8" down inside the coil -- too deep to get a pair of dikes on it. I've pulled on it as much as I dare, and it doesn't want to come out. Every book I've read on this just says to "remove the wire from the coil", but it must be simple enough that they don't feel a need to explain it in any detail. I'm ordering a new coil, which may shed some light on the subject, but would appreciate some help in the meantime.

 

[Plainsman]

Re: How do I remove the spark plug wire from a coil?

Will it unscrew? Just a thought

 

[Boatleech]

Re: How do I remove the spark plug wire from a coil?

Good thought; I was just wondering the same thing. I'll bring it back next time I'm at the boat.

 

[Boatleech]

Re: How do I remove the spark plug wire from a coil?

Another question - the new coil (Sierra) just arrived, and it came with a small thick-walled tube whose purpose I can't figure out. The old Mercury coil doesn't have anything like it associated with it.

What is this and what do I do with it? A ferrite noise suppressor, maybe?

 

[duckhunter314]

Re: How do I remove the spark plug wire from a coil?

If it's tie wrap your having problems with take a pair of pliers and twist the square part of the tie wrap then the wire should pull from the coil.
If it is an aftermarket coil twist wire counter clockwise as suggested by the previous posters.

 

[Boatleech]

The end of the story

The end of the story

Well, it was a dumb question after all. The wires just push into the well of the coil. I can't see what the Ty-Wrap was there for, and I don't see why it was so hard to get out. There's a brass crimped-on ferrule that looks like it's suppose to pierce the insulation and contact the wire, and thus conduct the spark to the brass liner in the well -- the wire itself doesn't make contact. I think corrosion may have made the wire/ferrule connection go bad in mine -- the spark plug-to-coil ground resistance was about 5Megohms, but the coil secondary itself was 986K -- i.e., the coil was fine. So I now have a spare coil.

As for the mysterious bushing-like thing that came with the new coil, it is in fact a bushing. It's not used on this motor, but is supplied in case you're replacing a coil on a motor that does use it. This coil (Sierra 18-5186) is used on many different motors.