Re: Gas spilling when being filled
THis is not uncommon in boats.
There are several factors. If the fuel fill hose has a long run, the fuel can back up in the line. This traps air in the tank. Be particularly suspicious if the fill hose appears to drop, then rise up to the tank. This will cause problems with fueling the tank. I've re arranged fuel fill hoses to have a steady drop to the tank.
If the boat sits on the trailer bow high, the fuel may be trying to fill uphill in the fuel tank. And, as mentioned, the tank vents can get plugged with wasps, the tank vent line can get kinked. One boat I was working on had the vent down in the bilges. The line broke off the vent fixture.
Take a close look at the fuel tank vent and hose.
I can usually hear a gurgle before my tank overfills. I've learned to shut off the pump and check the fuel level in the tank.