Gas tank vent issue

[shrimpman steve]

Ok, here we go. In the past as I was coming close to a full tank while fueling some gas would spit out of the vent nipple on the side of the boat the last couple of times I filled it, no warning from the vent and fuel back sprayed from the fill hole all over me. Next thing I noticed was a bulging fuel tank. So much so that it popped the fuel tank access hatch on the deck. I figured it must be a clog in the vent hose. I disconnected the vent hose from the tank and blew thru the hose, no clog. Reassembled and have the same problem. When I filled it yesterday before launching same thing. Got soaked in gas when the tank got to full and noticed the deck hatch popping up again. I though I would relieve the excess pressure in the tank by taking off the fill cap, but when I did no escaping vapors. After running for 10 minutes the catch cover in the deck was flush again. Boat is running fine but I obviously have a venting problem. I'm afraid the tank will split if it swells like that.

Help.

[dfish28]

That does not sound safe at all Steve... if i'm reading this right, you're able to blow through the vents but your tank still swells? I get the same issue with the whole gas coming through the vent when its at almost full, hate it when we are at the fuel dock just kind of twiddling out thumbs waiting for that moment of "OOps almost there" as we look the other way. One thing we have as a help is the flo-scan is dead balls so we know when to baby the trigger on the nozzle... but if you can blow through your vent I would really look into that. If its a poly tank that E crap may have gotten to it. when you disconnected it did you kiss the vent and try to blow through that too. hose could be fine but the fitting could have gotten a mud wasp of something... boat supply stores have an inline device as well you can put on the vent hose basically a whistle that when the airflow through the vent increases as you get closer to full the louder the whistle gets... Let us know what you find

[Bass_Appeal]

the vent hose coming from the tank should have a check valve in it , it could be allowing air one way and not the other , this causing like a backlash and when the tank heats from the dailey temps the tanks swells with no venting be allowed to release pressure ....i would check the valve or replace it if there is a spring in it the spring can corrode from the ethanol holding it back. or if you have an attwood style gas cap with the vent in it , a certain model was recalled for the venting issue i believe check online attwood gas tank cap recall

[Bass_Appeal]

come to think of it , might not be a spring in there , the ball in the check probraly rises to let pressure vapors out , but if boat over turned it allows the ball to flip to the vapor outlet side to prevent fuel from spillin out , so maybe no spring in side ..

[dfish28]

I was thinking check valve as well but Shrimpys info was saying he was still getting sprayed on full ups... Could be that as well still... It's a problem that should be not ignored till the culprit is found: if you can both suck and blow go deeper my man...

[shrimpman steve]

Going to check the check valve next.

No more talk about sucking and blowing, this is a fishing site