Fuel tank help

[GM man]

I've got a 31 gallon 87-91 LMC tank with the four outlet sending unit in my Jimmy. My problem is that when you go to fill up, within a couple of seconds of filling it'll shoot gas back out at you with some serious force. First time it did this, it almost hit a guy standing on the other side of the pump from me! The only way I've been able to put gas in, is to go painfully slow. Even the first notch on the handle is way too fast. The guy that installed my tank was a complete schmuck and it doesn't surprise me that he screwed it up, but is there something specifically I need to do to fix this issue? I'll just be guessing at how to correct it when I get under there. Thanks for any help

[stangtjk]

My guess would be that the main vent line that runs along the filler neck is plugged up or pinched....

[simicrintz]

Originally Posted by stangtjk

My guess would be that the main vent line that runs along the filler neck is plugged up or pinched....

That was my first thought as well. Had it happen on my Jeepster and as soon as I fixed it the problem got better (did not not clear up 100% and still burps back now and then if I am not careful). That sounds like the first place I would start!

[mister.freeze]

It’s a twofold problem in my experience. The filler neck is too narrow and the vent terminates in the filler neck. If you don’t need all 4 outlets, try making the extras vent somewhere