Wd-40 around crank seal. If it doesn't respond:
Try turning idle screw down first. If that doesn't do it, ( you'd be amazed how many times that's cured it!) fatten up fuel screws 1/4 turn.
Check your carb sync. I'd be amazed if those old carbs were anywhere close!
If it doesn't hang/idle for at least 5 to 10 seconds after it is hot and cleaned out good, you're too fat on the fuel screws anyway.