Personally, I would not use the third unless I was using a fuel dot or fueler valve. The fuel dot and/or fueler valve are designed in such a way as to prevent fuel from escaping or leaking from the system.

My suggestion - don't use it without a fuel dot or fueler valve. If the third lead does not have a hole in it (completely sealed), just attach fuel line from the lowest nipple to the carb and a fuel line from the higest nipple to the muffler (silencer). To fuel or drain with this type of setup is all done using the line to the carb. Just pull the line from the carb nipple and attach it to the line from you fuel jug.


Just my .0002,