When it is warm and quits running, does it spin faster than when it is cold when cranking it?

Get a compression tester (if you do not already have one) and tools to remove a spark plug. Check the compression with the motor cold and then take it out & run it until it quits. Pull a plug and check the compression again (in the same cylinder of course) and see if there is a notable difference. That will tell you at least if there is something in the valve train that could be miss-adjusted.

The reason for this is if you have a solid lifter cam and are adjusting the lifters as a hydraulic you could have everything too tight and once the motor warms up and everything expands you could/might lose compression. Un-fortunately if you have a solid lifter cam you might have already damaged some lobes.

Also check for spark at the plugs and from the coil to be sure you are ok there. Of course be careful when checking the spark from the coil wire. They actually have spark testers that you install inline so you can see it without getting shocked.

Just some random thoughts. I might be full if El Torro CACA.