getting ready to store my new deere s240 yard tractor.i am using stabil with my gas but was wondering about adding a fuel shutoff valve in line with the gasline so i can easily run the machine out of fuel and store with carb dry. (tank will be left full for condensation purposes). my question is should the shutoff be between the tank and the fuel pump or between fuel pump and carb.i am not sure if it would really matter. thx for any input.