I always fill through the pressure line. Because I use metal tanks, they don't blow up. Actually I have a capped overflow at the top of the tank which I open to vent the tank while filling. I run uniflow tanks, which means the pressure line is in the fuel. I have one set up here the engine is side mounted and the muffler is below the tank. On that set up, I have to replace the vent cap first, then reattach the pressure line. I found that if I replaced the pressure line first, then the vent cap, fuel would siphon out the pressure line and into the muffler. I got a couple of really short runs before I figured that out.[X(]

Jim