Reply To: Mercury CDM 835084A1 Electrical diagram Mercury Force 90 Trigger and stator

[billw]

I can’t remember, or did I ever really understand, why; but there was something about CDMs that relied on each other to work. I don’t see it in your diagram but there would sometimes be a situation where one cylinder had no spark but another CDM was causing it to happen. So the easiest way to trouble shoot it was to have a spare, known-good CDM and simply plug it in, replacing one CDM at a time, until you had spark on all cylinders. You’d test the charge and trigger voltage in the normal way but the CDMs themselves, you just replaced and checked until you found the right culprit.

Long live American manufacturing!