Here is some factory Edison RM and CD application information. There will be a Specification number on the aluminum tag that will match the installation. There is a number on the drive cup that will correspond to the lag angle.
The RM is a fairly hot magneto when in repair. They suffered from sticky goo seeping into the works from deteriorated insulating varnish from the coil and condenser issues. The multi cylinder condensers seemed to fare well but the single cylinder condensers did nor and can be very annoying to retrofit or rebuild. More on this perilous task in the repair section for this critter. Reinstalling the impulse drive cup to the armature shaft can drive one looney if not done properly. See the repair section for this other perilous task.
The CD is also a fairly hot magneto. Those who dare venture into early John Deere unstyled tractors like the A and D are probably familiar with these. Be vigilant when installing the coil. When it slides into place the end tends to tip upward leaving an air gap between the poleshoes of the magneto and the coil causing a wimpy spark.
Your magneto is probably out of warranty.
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