Air trapped in the tank

[legend 550]

New to me 98 Wellcraft 210 Coastal Fuel tank is 100 gal. Boat was fueled on the trailer before launch sitting level. After a weekend of use the floscan showed 27 gal used, sounded close compared to my other boat. At the fuel dock with the boat in the water I could only get 15 gal in it meaning there's a 12 gallon air bubble trapped in the tank. Is there a way to vent this or should I just forget it ?

 

[smokeonthewater]

Just forget it

 

[Chris1956]

The vent should be on the top of the tank, to prevent such an occurrence. I guess if the transom is a lot lower, and the vent is in the center of the tank, some kind of bubble is possible.

If the tank is plastic, you may be able to see the fuel level, so pull off the access panel and check it out. If the fuel pickup is in the bow part of the tank, and the vent is in the rear, they might be switchable.

 

[gddavid]

Check the fuel vent fitting on the hull for a blockage. They have little screens in them that can corrode to the point of creating a blockage. Also be sure the boat is level when you are trying to fill it,

 

[legend 550]

The fuel pickup is at the rear of the tank and the vent line is near it. Unless there's an internal line to the front of the tank I'd guess it vents at the low end. With a 100 gal tank I'm more worried about moisture with the tank not full.

 

[Chris1956]

Well, if you truly have a bubble in the front of the tank, and you fill the rear of the tank, no moisture will get in when the boat is moored.

 

[gm280]

I can't see how any air can get trapped in the tank. Especially if you can crank and run the engine without issue. Because that means the vent is open and allowing fuel to flow out as air flows in. Otherwise you would starve the engine for fuel and stop. JMHO!