Dart not restarting .

Probably heat sink flooded. When it does it, try holding the throttle open all the way while cranking. If it isn't fuel related, you need to test for spark whenever it acts up. To help keep it from happening, adding a spacer under the carb sometimes help keep the fuel from boiling in the float bowls. Make sure your heat riser is not stuck closed or partially closed. That can cause more heat in the intake manifold exhaust crossover under the carb.