gas engine fuel plumbing ? help

[itchntofly]

does anyone have a diagram of how to set up a 3 line fuel system for gas ? i know one is clunk to carb. one is vent to top of tank .but where does the fill line go in the tank, top or bottom ? if it goes to the bottm do you need to have a plug ?

[fhhuber506771]

The third line would be just to fill and drain the tank. It goes to a second clunk and needs a plug.

You can also just T into the line for the carb, since the diaphram pump in the carb will not alow you to flood the carb while filling the tank and it won't let you draw air while emptying the tank.