My 340 always weeped until I put a peice of 220 grit wetsand paper on a flat surface and sanded this **** out of my gooseneck. It was warped. Hasn't leaked since.
Did same used permex gasket maker very thin but all coated both sides bolted down to snap on wrench bite in hand tight no prob. Think there like tin valve covers everybody over tightens them and they warp and leak
