My husband has checked everything. He knows there is no spark, but that is not the case all the time. He can crank it over, but only 1 time out of 20 there will be a spark, but it seems to be completely random when it finally produces a spark. Once the mower does start it quits spontaneously as we are mowing. It will start right away, but then quits again. Is this two problems or just one problem? Where do we start after doing the normal things, spark plugs, etc.

These are indicative of the harder problems to solve Possibilities: coil, ignition module, points, condenser and flywheel to coil position. The problem your having is likely thermal in nature. Some items may not exist on your engine.

Check the small black "kill" wire that comes out of the coil. It could have a bare spot on it causing the coil not to fire all the time.

mine does the same thing and it will just cut off random while mowing but I know what's wrong with mine if your sitting on the mower with the hood up reach your left hand over above where your left foot sits while rideing it and there's a little black round piece with like 3 or4 wires coming out of it there like yellow red n black I think but mine and I've seen others that have shorts n them if u twist on it while trying to crank 90 percent chance it will fire because that's part of tha coil n kill . Its black and round and little about the roundness of a quarter n about10 quarters high.