I think the only way fuel could be coming out that hole would be if the welch plug above the hole is leaking..Take the cover off (4 screws) and check the plug above the hole....The WTA6 is the only Walbro that has this screen, called an idle field screen, in the Walbro book...Don't know what it's for.....
The Walbro factory customer relations engineer I called today was busy and couldn't return the call, maybe tomorrow....