Check for spark with a new well grounded spark plug to the cylinder top. If nothing is there I like to begin by disconnecting any sort of kill wire. Such as the key switch so you are not mistakenly killing the spark unintentionally. Once that is cleared remove the flywheel next for a visual inspection. If all looks secure you would want to make sure the gap is correct, that they do open and close as the crank is turned and that there isn't any corrosion. The striker on a match book cover works great to clean those up as one should never really file those. If the engine shut off leaving the points in a closed position moisture can collect there just enough to produce a tiny amount of corrosion causing them not to make good contact with one another. Then reinstall the flywheel enough to be able to spin the motor through and look for spark. If still nothing, well, then we can discuss more later but that's the easy quick stuff for now!
