gas coming out of vent .

[canman]

hi everyone . i have a 16 foot larson senza with a 140 horse johnson on it . when the boat sits in the driveway covered up all week i get gas coming out of the vent and going down the side of the boat cover , this only happens if it is sitting there with a full tank of gas in it . should i be loosing the gas cap before i put the boat cover on ? thanks . it has a 15 gallon built in tank ..

 

[fishmen111]

Re: gas coming out of vent .

I would not loosen the cap...too easy to forget to tighten it later. Make sure you stop filling at the first cut off and since you have a cover, store the boat as level as possible. The normal bow up parking does not help.

 

[dodgeramsst2003]

Re: gas coming out of vent .

Its the fuel expanding as it gets warm. Like the above post, leave the boat sitting level, and try not to fill it quite so full. Some boats are worse than others about this, has to do with tank design, location, fill hose location, and vent tube location. I know with my boat, if I fill it all the way up at the gas station, and then trailer it home, when I stop at a stoplight I will get some spillage. I try to not get it all the way to the top and seem to be ok.

Chris

 

[Coors]

Re: gas coming out of vent .

Do you have a tank vent? Is it not clogged?

 

[fixb52s]

Re: gas coming out of vent .

I found out the hard way to never fill mine full. I put in a new tank and filled it to the first pump cutoff. Even then, I had some spit out of the vent (I since installed a check valve in the vent line). The next day was really bad when I found fuel all over the side of the boat. The fuel expanded so much that it was running out of the vent fitting. I pumped out about 4 gallons to be on the safe side.

I don't know if this "corn" gasoline has a higher expansion rate than regular gas, but I can say it expands A LOT.​

 

[jay_merrill]

Re: gas coming out of vent .

Lots of good suggestions and the bottom line is that you are filling your tanks too full. As you fuel, listen to your tanks ... you will hear a sort of "gurgling" sound as the fuel level reaches the top. This will happen not long before the automatic cutoff on the fuel nozzle "clicks." The time to stop fueling is when you begin to hear that gurgling sound, not when the auto-shutoff engages, because this will leave enough room for expansion later on.