Steve might be a little more help than I can be as I am using a 2-stroke and am
not familiar with 4-stroke set ups. I use a Tettra tank with 3 lines , one filtered line
to the carb , one filler/vent line to a fuel dot on the left side of the cowl , and one
vent/pressure line with a tee in it - one side to a fuel dot next to the other dot and one to
the muffler with a one-way valve in it so pressure can go to the tank but fuel will not
go into the muffler.
You can open both fuel dots and fill from either one and the other becomes the overflow.
One thing to be careful with is make sure the tank is installed on the carb centerline , not
the engine centerline , this is important on a 2-stroke and I assume on a 4-stroke as well.

tommy s