1988 gulf stream on John deere Chassis

I have a 1988 gulf stream on a John Deere Chassis. The fuel pump was working but had carb trouble, I took the carb off and had rebuilt Now I cannot get the fuel pump to work. It has a fuel interrupter switch, does anyone know where it is at and how to reset it. It has a 460 Ford engine. I am also wanting to know if anyone has an idea about what might be wrong if it is not the switch, why it would just quit after the removal of the carb.

I might have dirt in the gas tank, does anyone have an idea of how to clean it without dropping the tank.

Thanks for any help you can give me.

Jerry