1976 Elsinore MR 250 no/spark/coil/magneto/

I would pull the plug and reattach the spark plug lead and use a test lead with alligator clips to provide a ground path to some likely spot on the engine like a fin or something then hook the other end to the plug body (threads). Darken the room or wait till night if you can't darken the room. Kick engine over with all appropriate things turned on for ignition. If you don't see a spark you will need to look deeper... Could be any of the following if you don't get spark: 1. points not making and breaking as they should 2. Bad points wiring 3. Bad condensor 4. Bad spark plug(fouled) 5. Bad High tension lead to plug 6. Bad coil 7. Bad ignition switch 8. Bad emergency kill switch 9. Short in low tension wiring

Magnetos are incredibly reliable so I've tried to list in order of the way I would try to eliminate the issue. You might want to check 7-9 closely if the the first couple of things don't help or lead you to the fix. Things with actual moving parts like switches are weak points in any electrical device. If this is a real magneto system it is important to note that the battery and charging system has no bearing on getting spark to run the engine.