Hate to start another thread ... but.. help !
how is your coil mounted -- vertically, or horizontally on the intake?
We had a problem with the '83 D150 440 shop truck doing the same thing after installing an MSD setup............... suggested moving the coil to an upright position rather than laying on its side. Apparently the cooling oil inside doesn't "go all the way to the top" and they can get hot and quit working.
Cudachick has a point. 30 years ago, nobody worried about this, and millions of Ferds came with horiz mounted coils. If the coil is horizontal, at least make sure the terminals are DOWN and not UP.
If you are measuring coil voltage with key "in run" and engine OFF, this low voltage may be perfectly normal
With the engine running however, depending on what coil/ ballast, etc, and the system voltage, AND RPM, coil voltage can vary anywhere from 7 to 12 (14V charging). This is because the coil voltage is a pulse and the duty cycle changes. If the duty cycle pulse was 50%, it would be half battery, IE 6 if not charging (but running) and 7 if running at 14V
What are you using exactly for coils/ ballast/ box? Are they everyday Chineseo parts store stuff, or MSD blaster/ etc, or what?
Also check our running charging voltage
Basically, in simple terms, you need the coil and ballast matched
DO YOU (I hope not!!) routinely leave the key "on" with engine "off?"
