Re: Old Chrysler 55hp - No Spark
Yes, a 12 volt coil is a 12 volt coil. It would be nicer to have original equipment but you work with what you have. That engine is set up with a12 volt blue wire to the positive side of each coil. The white wire goes up to the points. when the points close voltage flows through the primary circuit of the matching coil and builds a magnetic field. when the points open, the field collapses, and passing through the fine windings of the secondary, generates a high voltage to jump the sparkplug gap. SO: The coils are nothing more than DC step-up transformers.
Condensers primarily serve to absorb and cushion 12 volt flow through the points, preventing arcing across the points as they open and close, and extending their life. SO: If a condenser is shorted no voltage will flow through the primary and no spark will be generated. However, without a condenser, voltage would jump the point gap as they opened or closed, changing the dwell and no spark would be generated.
Points are set to .020 open on a high point. This opening will determine the amount of time the points are closed (dwell) and directly, the satuation of the primary windings, thus the strength of the magnetic field. Too much opening = too much dwell and not enough time for the field to collapse. Too little opening = not enough dwell and a poor, weak magnetic field. Both conditions will pevent generating a high enough secondary voltage to jump the plug gap. Like Goldilocks, one is too big, one is too small, and one is just right.
With old engines that have not been used in a while, 90% of the time a spark problem will be dirty or mis-gapped points or bad condensers.
If you are NOT getting voltage through the blue wire to the positive side of the coils, then the ignition switch is most likely bad. You could "jump" from red to blue on the engine terminal board andcrank the engine. If you then get spark, replace the ignition switch
