gas fill issue

[highpowerdad]

So, what would cause the gas fill to “back up” into the fill neck. Here is what happened, gas gauge says boat is empty, I buy 25 gal of gas in 5 gal cans, start to fill…boat is in the water…get 3 gallons in and the pump I am using shuts off…gas is at the top of the fill neck. Check gauge, still empty…think gauge must be bad, take boat out to shake up the tank a little to see if there is an air bubble, come back, try to put more gas in. gas comes back to the top of the fill neck after about a gallon and THEN…there is a big swirling, venting of air for several seconds (and some gas also was pushed out) – it wasn’t bubbling, it was venting air from (I assume) the vent hose next to the large fil port, and then I was able to put in 20 gallons without issue. Is there a vent tub “flapper” or something that is sticking, or a clog in the line? Thanks...

 

[alldodge]

Depends on the year of the boat and how the vent lines are routed

 

[highpowerdad]

Depends on the year of the boat and how the vent lines are routed

good point... 2005 fourwinns 190 horizon with 5.0 GXI volvo penta. at the fill neck it looks like one large pipe (where the nozzle goes) and a small vent "head" with, I think, a screen on it...I would assume it is plumbed like most other "runabout I/O, but if I need to take pictures to help with the answer, I can do that...

Scott R.

 

[alldodge]

Then you should have connections which resemble the pic.
Note there is a check valve and how the hose lays

 

[JimS123]

Your vent and gas fill lines are BOTH plugged. Need a rotorouter or replace the lines.

If you go the easy way, better check your fuel filters for contamination.

 

[highpowerdad]

The lines are not plugged, but the air was trapped, I guess the check valve must be sticking, and when it opened, there was a rush of air...something to fix this winter...

 

[JimS123]

If the check valve was stuck, then semantically the line was plugged. Sounds like something I'd want to fix now before I used the boat again.

 

[ahicks]

If there is a low spot in the vent line, and the tank is ever overfilled (or fuel is sloshed in there), that low spot may fill with gas - causing an issue like described. A total pain to fill until the low spot is purged. For the repair, the plan is to find that low spot and do SOMETHING so that the low spot disappears. Might be something as simple as a tie wrap holding the vent line up for instance....

 

[highpowerdad]

If there is a low spot in the vent line, and the tank is ever overfilled (or fuel is sloshed in there), that low spot may fill with gas - causing an issue like described. A total pain to fill until the low spot is purged. For the repair, the plan is to find that low spot and do SOMETHING so that the low spot disappears. Might be something as simple as a tie wrap holding the vent line up for instance....

Interesting, all the lines are visible in the stearin, I will have to take a look and see if the vent is dipping down somewhere between the fill neck and the tank, thanks