Robrv3
By chance on the Chevy chassis ?
Both my last two MH's were on the Chevy chassis and the fuel line from the filler nozzle to the tank were almost flat horizontal to tilted the wrong way !
I noticed that when I filled up at most Chevrons I didn't have a problem, but when I filled up at Arco's ,76,and Shell ,,, click click click stand there and hold the pump nozzle turning it in every direction for 15 minutes to fill it up.
Someone else mentioned what Burghcoder said about checking the vent hose.
Also the picture IAMICHABOD posted look close at the filler opening and the pump nozzle sometimes the vapor recovery hose over the actual fuel pipe doesn't get collapsed enough to seal and will cause the same thing...