The most likely culprit... You are using a coil that requires a ballast resistor to drop the line voltage from 12.6v down to something more manageable. Most electronic ignitions (and point ignitions...) require a 3ohm coil. This drops the + terminals voltage.
Ohm between the + and - terminals and you ought to have around 3ohms... if it has an internal resistor. (with the key off...) 0 ohms, and you've got a shorted coil.
If your coil shows less than 3ohms, but doesn't show continuity... you can install a 2ohm ballast resistor in the positive line. Points ignitions (Kettering) use low voltage to keep from frying the points. The higher the voltage the better it arcs, and the more amp potential... great for lighting
off the spark plug
, not so great for stretching time between point replacement. Ballast resistors were Stock on old fords and chryslers for many years, go to the parts
store and ask for an "ignition resistor." It'll be a ceramic rectangle with a coil inside, one screw mounts them to a heat sink. On cars, that'd be the firewall... on the boat, a big piece of aluminum
will work. These things get really hot, so wait until someone that knows boats writes back. I don't know if they are coastie approved.
Now turn the key on, and check the voltage between the coil terminal and the positive pole. You will have to turn the motor
over until the points are closed... If this is 12v, you have a dead short and no resistor in the coil. Less than 12, and you've a semi-functional coil... It ought to drop less than 9v if you have an internal resistor. With your external resistor, it'll be a lot less. (5v +/- going into the coil... No big deal, points ignitions work just fine on 6v systems too... and their coils have resistance too!)
There is a screwball here, if the switch provides 12v to the coil bypassing an external ballast resistor for easy starting, and somebody in the past wired it backwards... You can check it while its running, but... Man that fan belts mighty close!
It's also possible to wire in the electronic ignition backwards, they don't much care for that. Most cannot take 12v, and do not like having the key left on with the points closed (Dead short... Coils will let the smoke out if you leave the key on for a few hours too!)
Coils will still start the engine
if you wire them in backwards as well, double check this... Coils wired backwards get hot.
Extreme point gap will increase the operating temperature of the coil as well, think charging
time... Dwell still happens with an electronic box, so check it... but its not easily adjustable.
All this being said, if you have an infrared pyrometer... or quick hands, reach back there and see if its blistering hot or if you've got a little oil leak
dribbling on it. Your coil is filled with oil
, so if you have smoke coming out I'd bet a dollar the case has a crack for it to escape.
It's one of the grand things about electronics
... when they start getting hot, their resistance goes up. When the resistance goes up, they get hotter... until they let out the magic smoke.
Hope that helped!