Im using the same size line as the fuel line, fuel line is snug but the vent isnt.
The full tank bog is when i fill it up to the top and fire it up it wants to bog and die. Until about 3/4s it runs great then. After i put most of it together i filled the tank full and fired it up, it did not do the bog but i was just wondering what could of caused it.
The fuel line on that little fitting gets pulled up from inside the tank for the vent line. You keep pulling it though the hole so the the fitting is up tight in the hole, with the line sealing it off from leaking. The duck-bill valve goes on the bottom side of that fitting.
As for the bogging? Do you have the carb adjusted right? Rich enough? You did do a muffler mod to it, that could be off a tad. And, never assume the fuel filter is good, just cause it looks good. Believe me, I been there,,lol
Gregg,