So I have been chasing a vapor lock issue for about a year now. Changing coil, plugs, points, condenser, electric fuel pump, new lines, you name it. It wasn't until I started it with the hood open once and discovered the muffler was broken. It cracked around the right side inlet pipe flange. I got it welded up and mowed 2 weeks worth of grass. I pushed it and it made it through all of it without an issue of wanting to shut off. I mean mowing grass a foot tall in spots. Hopefully this is it and I didn't just jinx myself...