Your engine is probably a Tecumseh model HH70. If you look very hard on the shroud, by the spark plug, you should be find the model and spec numbers. With the old points system I suspect you may have a bad coil or it is not timed correctly. The timing of these coils are very touchy and you need to know what you are doing or have exact tools. Plus, I doubt you measured the resistance of the primary and secondary windings correctly. Attached is a service manual, please carefully read chapter 8 and retest the coil. If you need more help, find the numbers and post back.
https://www.mymowerparts.com/pdf/Te...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf