Why does an exciting coil die

[FryeClub91]

Hello, I'm doing a rebuild on a 91 DS 341cc KF82 flathead. I pulled the motor and replaced a few things in the crankcase. After putting everything back I had no spark. Battery is strong, starter runs fine. I tested the exciter coil via the 3 prong connector coming from behind the flywheel as per the manual. The ground tested find, but no reading when testing resistance between red and brown. Manual says to replace the exciting coil so I'm looking for that now. I'm a bit concerned I'm going to replace that part and short it out again because I haven't found the root cause. I believe its original...so 30 years...I guess it could just been coincidence. Any thoughts on what causes a exciter to die and things I should double check before firing it back up again? Thanks.

[Springbok]

I don't think there's a solid reason that any of us can point to for the failure. Just wear out over time I would imagine.

[FryeClub91]

Thanks - I just hate how it happened after I put everything back together again.

Fingers crossed for round 2...coil is on the way.

[xltaylor]

Might as well take the old one out and check for a broken wire. Skin the insulation right as it goes goes into the coil and probe from there.

[FryeClub91]

Thanks for the hint xltaylor. I looked at wires, all good there. However it does look like I gave the connection on the coil a good whack somewhere along the way. The wire and the blob-like glue/sealant was shifted and a bit lose. I wiggled it back and it started registering resistance again. Looks like my general clumsiness cost me some $$$ as the new coil is already installed and running great. So I guess the answer to my original question of why an exciting coil would die is just me not being careful (nitwit). There are no coincidences.