Having trouble with fuel tank venting on a 335xpt and need a vented gas cap. A little while ago the original tank vent was changed but either something with it went wrong or it's not adequate because I am getting a stall out part way through each tank of gas. If I open the filler cap for a moment then the issue is solved for a while. I haven't found a fuel resistant sealant to fit a vent in the filler cap so my attempts have resulted with weeping fuel. Any suggestions would be appreciated.