Is your an electric start ?. I believe only those models use a coil. Kickstart rely on the magneto located beneath the flywheel. For kickstart models - beneath the flywheel you'll have (1) light winding coil and (1) magneto. For electric start you have (1) light wound coil, (1) ignition winding coil, then a stand alone ignition coil mounted on the frame.
Check the spark plug cap for corrosion. Based on age these can be a problem delivery spark to the plug.
Have you tried bypassing the ignition switch to see if the switch is interrupting the power from the magneto or coil ?. Could very well be a wiring issue.
Check all grounds (engine) or coil (if equipped) for solid grounding ?.
If you have an electric start model then the coil could very well be the problem. This assumes the flywheel coils or magneto are good.
As for parts - Have you tried calling Richards ?. Ebay is another source. I own a Homer and have purchased several Homer parts on Ebay. Parts are general not too difficult to locate.
Ebay BS50 coil -
https://www.ebay.com/itm/133873665382Perhaps some of this info helps ..
Kevin
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