I was not aware of the M151 coil overheating problems. Definitely worth checking. Turns out the TM 10-1513 has the dwell at 47 degrees for the L134 - later corrected to 42 degrees. The duty cycle at 42 degrees is 47%. Running the dwell to 47 degrees would up the duty cycle roughly 10%....which was probably pushing those coils and causing points to burn prematurely because you had to set the point gap significantly under the .020 spec to get that dwell. Love the well meaning machine shop! Bet that owner was scratching his head a bit! Turns out that there were two versions of the Champion 6 flywheel (thanks Howard)...and this one is for a car with a driver side starter. O well!
Replied on Dwelling on Vacuums & New CJ's! ShopTime™ 326 (S)
02 Aug 07:32
You are very welcome! I am pretty sure that this particular Sears model cannot handle 24 volts. If you start looking on Ebay, you will find several commercial varieties with 24 volt capability. To my knowledge, 24v was never common except military so you may end up having to find a military version.