I have a 1971 Fiat 850 Sport Spider. It has been sitting for 10years or so. I changed the plugs, changed the oil, cleaned the oil centrifuge, put new fuel in it. It runs great when I add fuel to the carb. The fuel pump is good. I ran a line from the fuel pump into a bottle of gas and it runs. I am wondering if it is a vent problem with the tank. I am at a loss. If anyone has any suggestions I would be open to them. Thanks.