Often when I'm filling up with gas on the water, the auto-shutoff of the gas pump is activated at the exact moment the tank is extremely full, causing a "burp" of gas on the deck and sadly, some fuel sometimes spills in the water. I've tried sqeezing the gas pump handle less, but the pressure just builds too quickly no matter how slow I go. Is there a product that anyone knows of that will fit on or in the fuel fill pipe that will stop this overflow from happening?
To answer your question: Yes, this product is one I know to work well: http://www.parker.com/portal/site/PARKER/menuitem.7100150cebe5bbc2d68067...
However, before I looked to consumerism for the solution, I might suggest you check out your vent line. Start with the vent fitting and make sure it not clogged with debris or an insect nest.
Nexy, check the routing of the vent line. There should be no low spots and the vent line should be entirely above the level of the tank for the length of its run. If not it will hold fuel as the tank gets filled and create the "burp" that spills fuel out your fill.
Fuel spillage at marinas is a double whammy to the environment because people often add Dawn soap to the water to disperse and sink the fuel. This traps the fuel in little clumps and sinks it, where it gets into the sediment and creates real problems.
The solution is dripless fueling technology which has been known about in the fuel industry for a while. Nozzle manufacturers are waiting for government to mandate its use. While we WAIT for the government, Strictly Green has a retro-fit device called the DropStopper that will stop fuel spillage at marinas and all fueling stations.