I''m not sure I follow what you did but, you do need to have the tank vented so that line needs to stay open. You do need to plug the hose that goes into the carb where (i assume) your primer bulb went in. All you should need from the tank is the fuel supply line into your carb and a vent to air. At the carb you need the one nipple plugged (usually some fuel line with a screw in it) and the other nipple has your supply line. I apologize if that is what you were saying, i just wasnt following. If you are getting fuel to the plug it should fire. Maybe you just need a starter on it to get it going and adjusted. Others may completely disagree but id hook that starter to your 18V and give it a try