I use a suction gun with a plastic hose on the end. Cheap from napa. I keep it clean and use it only for this purpose. It can get right down in the bottom, with very little left. I would pull the carbs off also and clean them if the sled has sat very long. Check all the fuel lines and vacuum line from engine while your there, they will harden and crack with age. This will save you much trouble, any prevent a burndown.