I keep a small outboard tank and hose in the shop with 40:1 XPS-II premix in it, comes in handy to show people what side of the fuel system their problem lies. Install a line clamp on the fuel supply to the pump inlet and remove it, slide the end of the outboard tank hose on and fuel tie it off and pump the primer and crank it.
You'll find out in a real hurry if the problem lies on the fuel supply side of the tank/vent/filter/selector/lines or in the fuel pump and carbs.