Ya your overheating and possible top end damage it at 19° before top dead center 1.5=19°Btdc
Time @.8°or 14° before top dead center to start and if you run cool below 400°F on your head temp gauge then you could add more timing but I doubt you run cool enough ever at 19° before top dead center or 1.5 mm.
This regard the Za50 timing on chart and time the same as a e50 that timing is for stock cylinders not kits. I don't know why a za50 is listed with higher timing anyway. Mine run fine even a little below 14° on the flywheel.
Just another wrong puch thing in wiki like hardwiring, running .05mm za50 shims, full advance timing, using a piston stop, no mention of magnum ll having spoke wheels saying only #4 cylinder is a 1 hp restricted when every number cylinder including a hi torque can have a restrictor in it amongst other erroneous information I guess.
72 jet is fine if 222 atomizer even for a 12mm bing.
Make sure you have perfect gas flow. Don't run without a temp gauge unless you like buying new kits