briggsboy,
It sounds like either a tunning problem or dirt on the fuel pickups in the tank.
What I would try first is remove the carby flush out the tank and clean the screen in the carby.
If that does not work you will have to remove the primer on the side of the carby. It has a small ball bearing that acts as a valve which also can cause you problem.
Here is a picture of the carby that might help you when taking it apart.