I was mowing and about 1/2 through, the mower died. Would not restart. I waited about 15 minutes and it restarted, but died within 3-5 minutes. Then I couldn't get it to restart at all. I changed the spark plug, check all wires attached, it has gas and oil to correct level.
Any suggestions?

Try looking at the air cleaner.

Could also be caused by the coil getting hot and separating internally, do you have spark after the engine dies?

I had a similar problem a few weeks ago I tried everything that is listed above. Mine would start then run for a min or so then I'd have to wait a few minutes then I could start it again for a min or so. It would stay running if I shot some starting fluid in the air filter when it was about to shut off. But anyhow I ended up taking the carb off and cleaned it even though it wasn't dirty it did the trick. Hope this helps

Start with the fuel filter first to make sure the carb is getting the fuel amount it needs on demand is there. After that check the bowl float and needle and seat valve which also controls the fuel amounts to carbs demands.

The "letting it sit gives the chance for the carb bowl to catch up on gravity/siphon feed fuel lines.

A fuel solenoid not working properly can also cause this to happen.

Start at the beginning and go from there. Take as much out of the loop. I do know for a fact that the gas with ethanol is playing havoc here on small engines and gumming up the carbs,

Lately I have been using "Sea Foam" and spraying it in the carb to clean it out while its running and had a lot of success in that. I now add the additive in the fuel cans for preventive measures. I was Just at a Yamaha shop last week and they were having the same problems with the bikes and the water craft..

That said lets check the ignition coil strength. Use a spark plug that you know that works. Cut off the curved end that goes over the electrode. Ground plug and see if the plug makes that extra jump in coil strength if not most likely a bad coil. Check all wires and grounds.

Hi,
Well, this is a push mower, so two things are invariably the culprit; restricted fuel flow or ignition module. The fuel filter, if present, is the screen in the bottom of the tank and generally ony susceptible to dirt/debris accumulation. The seat to the inlet needle is the most likely culprit. Alcohol or other additives to fuel can cause it to swell which drops the float level and limits the entrance of fuel to less than that required. Believe it or not, a #5 crochet needle is one one the best tools for replacement. Use the hooked end for removal and the other end to insert and seat the new seat (comes as a kit with the needle and keeper.) I have also used the blunt end of drill bits, hex wrenches and small clevis pins. Requires firm pressure to seat and the ring on one side "goes in first, never to be seen again."
The ignition as a rule takes a bit longer to fail. Also, usually takes a bit longer to return to operation.
Either one would do the wait a few minutes and it restarts; time for the fuel to refill the bowl or the ignition to cool.
I vote for fuel!
Peace,
Clarke