Repairs Valves are adjusted right the engine starts, but on restart the engine with not turn

Here's what I'm working for my cousin .. a 2014 Craftsman 917.288516 lawn tractor with a Briggs single cylinder 331877 2371 G5 engine. At first the engine would not turn over, but I could hear the starter trying to engage and turn it. My solenoid and starter tested good, with the spark plug out the engine turns freely, so I set the overhead valve adjustment to the specs of .004 on Intake and .006 on the Exhaust. Put cover on and the spark plug .. sure enough as I sat on the riding mower foot on the brake - turned the key and the engine turned over and it fired up and ran. I shut it off ... then after a couple of minutes I tried to start it again. But here again it was acting like it did before the adjustment. So is there something else I'm missing let a relief switch or safely thing - I need to consider?

Thanks for any help in this matter (the Youtube videos sometimes work, but not always)

Recheck your valve clearances.