Check to make sure carb, intake gaskets are not blown out, hard. There's been some issues with improper placement of gaskets. The heat riser gasket needs below the drip pan. Or 1 st gasket on the intake. It's 1/8" thick. Then the pan, governor etc.
check your flexible vaporizer hose at the vaporizer outlet. They rot from the tar sitting on them and soften up and leak. Causing hard starts and or no start.
Also slow path solenoid fills up with tar if the vaporizer hasn't been serviced properly.