Chainsaw Repair

I just got a real nice older red Craftsman 18" Poulan.It starts and runs just perfect.Only problem was, when I turned it clutch - side up, fuel was pouring out of the tank.I checked the cap, put a new o-ring on it, no better.I pulled the starter cover off to find an extra fuel line hole in the top of the tank.This carb. Is a , Walbro has no return line, so I suspect that other hole must be for a vent, but the parts list doesn't show one.Anyone have any idea or run into this before? I ran an extra piece of fuel line with a restricted tiny hole in the end of it,ran it up over the top of the carb so it is higher than the tank for now.Is there supposed to be a factory made vent for this one?The filler cap isn't vented.Thanks!...Ted.

Poulan 3400 3700 4000 showing the duck bill valve in tank vent line. 2 pieces needed.

Pic from member chainsawr

Yes

 I usually run a long length of line into tank. Put the plastic vent fitting in line then duck bill goes on it. Then pull the line on the outside back up till the duckbill fitting is seated to tank hole.



530026119 duckbill vent

530024475 vent fitting

Thanks for the help. I ordered the right one. Much appreciated!, Ted.