We also have this problem. I've sent this thread to Thumper at the factory now that it appears to be "endemic." We have tried several things that have not worked, including relocating the fuel filter and pump for the genset from here to the lazarette, and was about to do the Peggy Hall "hot rag wrap trick" on the hose to see if that was the issue, followed by the Saran Wrap treatment. Strange that it is only this compartment - the starboard side fuel fill area doesn't do this. Yet, I guess...
About the slow fill - We had the factory install 2 1/2" fuel fill hoses vice the standard 1 1/2" and that has helped immensely. Even if you don't have the 2 1/2" valve at the tank, the larger hose up to the nozzle can alleviate the nozzle's constant auto shutoff the smaller hose causes. For the vent problem, I'm as we speak installing a seacurefill (Google "seacurefill" - Sailnet won't let me post a link!) fitting at each fill. I'm hoping this completely eliminates really slow fill and also any blow back I might get despite the larger hose because, during filling, the vent is directed into the fill alongside the nozzle.
Bob 'n' Sue Cross
PSC 40 #60
PSC 40 #60