Gas Vent Spilling Fuel while towing

[rocklydockly]

I have a '95 Rinker 232 Captiva 5.7L Bravo III. It has a 72 gallon belly tank with the tank vent mounted high on the port side above and to the rear of the fuel filler cap. When I tow to the lake, the vent spill gas onto the swim deck. It even did this yesterday on the way back from Lake Powell with a half tank of gas. It spills very easily when tank is full. The vent is there for a purpose, can I plug it/tape it shut while towing? I'm wasting fuel, getting gas all over the fiberglass, and it's potentially a hazard. Any advice would be appreciated.

Please let me know if this question belong in a different forum.

 

[Don S]

Re: Gas Vent Spilling Fuel while towing

How low to the water is your vent? If it's real low, you can put a big loop of hose on the inside to raise the height of the vent without actually moving it.
I wouldn't cap it, it needs to be open to the air for expansion and contraction while towing. Tape will never hold back the gasoline.

 

[dingbat]

Re: Gas Vent Spilling Fuel while towing

It sounds like your vent line is "water logged". There should not be any fuel in the vent line at all let alone enough to spill.

Remove the hose at the vent and blow back through to the tank. This will clear the line and stop the leaking but you need to find out what is causing the line to fill with fuel.

Check to make sure that the vent line goes up uphill from the time it leaves the tank. At no time should the hose be lower than the fitting on the tank. If it does you'll need to reroute it correctly.

 

[rocklydockly]

Re: Gas Vent Spilling Fuel while towing

Thanks for the advice so far. Is anyone familiar with the Racor LG50? It is supposed to be a gas/air separator that will allow air/fumes to escape, but no liquid gas to spill. I saw several praising it and one or two saying it didn't help. Seems to have been quite an issue for Malibu owners.

 

[fixb52s]

Re: Gas Vent Spilling Fuel while towing

I had a problem with mine spitting fuel from the vent when I filled it up the first time after replacing the tank. I found out the next day that the gas would expand from the heat of the day and start leaking from the vent. What I found is this vent line surge protector. It is really nothing but a simple check valve that closes up when liquid or pressure hits it, but opens for normal venting. I am having problems linking the page, but search the Iboats store for Attwood Part # 1675-6.

Since I installed it, I have no more problems with fuel sloshing from the vent. I also am a lot more careful when filling the tank by listening for it to "gurgle", then shutting off the pump. I also don't fill it full unless I am on the way out to the bay.​

 

[tashasdaddy]

Re: Gas Vent Spilling Fuel while towing

position on the trailer and the boat being bow high, could also force the fuel up the vent line. if the bow is high, and the fill and vent are at the stern of the boat, it the fuel is going to seak level. thus it is going to go up the vent. either don't fill it so much, or reposition the boat. so the tank is level.

 

[jeeperman]

Re: Gas Vent Spilling Fuel while towing

You might also want to check and see what condition the gasket is on the filler cap. Or see if the filler cap is at all vented also.
It could be that while being towed at highway speeds, which are most likely faster than when on water, the airflow over the vent opening is causing a vacuum and is sucking the gas up and out the vent line. Of course air has to get in from somewherelse to allow the gas to be sucked out the vent line at that time. Thus check the possibility of the filler cap for leaking air.

Does your vent opening have a little "hood scoop" over it? facing down or towards the stern?